Ganoderma spore powder

Ganoderma lucidum is traditionally used to prevent and treat some diseases such as liver disorders, hypertension, insomnia, diabetes, and cancer. G. lucidum spore extracts are also reported to share similar bioactivities as extracts from its other parts. However, there is no systematic review that elucidates its pharmacological effect. Our aim is to comprehensively summarise current evidence of G. lucidum spore extracts to clarify its benefits to be applied in further studies. We searched five primary databases: PubMed, Virtual Health Library (VHL), Global Health Library (GHL), System for Information on Grey Literature in Europe (SIGLE), and Google Scholar on September 13, 2021. Articles were selected according to inclusion and exclusion criteria. A manual search was applied to find more relevant articles. Ninety studies that reported the pharmacological effects and/or safety of G. lucidum spores were included in this review. The review found that G. lucidum spore extracts showed quite similar effects as other parts of this medicinal plant including anti-tumor, anti-inflammatory, antioxidant effects, and immunomodulation. G. lucidum sporoderm-broken extract demonstrated higher efficiency than unbroken spore extract. G. lucidum extracts also showed their effects on some genes responsible for the body's metabolism, which implied the benefits in metabolic diseases. The safety of G. lucidum should be investigated in depth as high doses of the extract could increase levels of cancer antigen (CA)72-4, despite no harmful effect shown on body organs. Generally, there is a lot of potential in the studies of compounds with pharmacological effects and new treatments. Sporoderm breaking technique could contribute to the production of extracts with more effective prevention and treatment of diseases. High doses of G. lucidum spore extract should be used with caution as there was a concern about the increase in CA.

Introduction and background

In the past, lingzhi has been known as a magic herb as well as an auspicious symbol by the Chinese. It is also known as "reishi," "shenzhi," and "xiancao," which mean good fortune and mysterious power. Taoism played an important role in promoting lingzhi for either medical purposes or otherwise. In the ancient era, people used the fruit body of Ganoderma lucidum, which has bioactive compounds, including sterols, triterpenoids, fatty acids, and carbohydrates. G. lucidum is traditionally used to prevent and treat some diseases such as liver disorders, hypertension, insomnia, diabetes, and cancer [1]. G. lucidum is known for its pharmacological activities that help promote human health [2].

G. lucidum spores are the fungus's mature germ cells, considered the essential and best part of the G. lucidum fruit body produced during the reproductive stage [3,4]. However, there are very few studies on G. Lucidum spore extract because the extracting procedure of the sporoderm is very difficult [5]. In recent years, thanks to spore-breaking techniques, the compounds inside G. lucidum spores have been studied more. G. lucidum spores have effects similar to the fruit body; moreover, their bioactive compounds, including sterols, triterpenoids, fatty acids, and carbohydrates show higher concentrations than other parts of this fungus [3,6]. Understanding the biological effects, dosages, uses, pharmacological mechanisms, and safety of G. lucidum spores will help increase the effectiveness of using G. lucidum spores as well as developing products from them. However, no systematic review has been reported on these data.

Therefore, in our study, we summarize the existing evidence to assess the biological activity and safety of G. lucidum spores and their compounds with the help of a systematic review.

Review

Methods

Our systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist (Appendix 1) [7]. Our review protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO) (ID number CRD42021279806).

Eligibility Criteria

All types of original studies (in vitro, in vivo, clinical trial, case reports, retrospective study), published in English up to September 13, 2021, which provided information about the pharmacological effect and/or safety of G. lucidum (lingzhi or reishi) spores, as well as their compounds, were included. Articles that only reported the efficacy of G. lucidum fruit bodies, mycelia, or other species of Ganoderma but not G. lucidum, and studies with unreliable data (such as abstract-only articles, conference papers, theses, posters, editorials, and letters) were excluded.

Search Strategies

The search was performed on the following five databases: PubMed, Virtual Health Library (VHL), Global Health Library (GHL), System for Information on Grey Literature in Europe (SIGLE), and Google Scholar by search terms given in Table 1. To find other relevant research, a manual search was conducted utilizing the references of the included articles.

Study Selection and Data Collection

We used the WebPlotDigitizer tool at https://automeris.io/WebPlotDigitizer/ to extract data from the chart. The search results were automatically filtered for duplicate entries using Endnote X8.1 (Clarivate Plc, London, United Kingdom). Two independent reviewers selected articles based on title and abstract screening, followed by full-text screening. Any disagreements were resolved through discussion. Two independent reviewers extracted data from each article. The main data were the preparation methods of G. lucidum spores and their pharmacological activities. Data were grouped by pharmacological activity and study design.

Risk of Bias

The modified Consolidated Standards of Reporting Trials (CONSORT) checklist [8] was used for in vitro studies (Appendix 2). Regarding the introduction, all of the studies included a structured summary of the trial design, methods, results, conclusions establishing the scientific background, explanation of rationale, and the specific hypotheses to be examined. Randomization criteria (to assess sample standardization) and protocol criteria were not applied to assess study quality. A study with a score of 9-10 was considered "low risk of bias", 7-8 was considered "moderate risk of bias", 5-6 was considered "high risk of bias", and a score less than 5 was excluded from our systematic review.

In vivo studies were evaluated by the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE)ʼs tool (Appendix 3) [9]. A “yes” judgment indicated a low risk of bias, a “no” judgment indicated a high risk of bias, and the judgment was considered “unclear” if insufficient details have been reported to assess the risk of bias properly. Cohort studies and case reports were evaluated using the Study Quality Assessment Tools (SQAT) [10] of the National Institute of Health. Ratings for each item ranged from 0 for potential flaws to 1 for good practice (Appendices 4, 5). Additionally, we followed SQAT’s instructions to categorize "NA" (not applicable), "NR" (not reported), or "CD" (cannot determine). These were used for ambiguous fields when our investigators were not sure what score should be allotted, which suggested scientists should be cautious of potential flaws while adopting data from those studies. Each item received an equal number of points in the final percentage calculation. The scoring cut-off at 75% or above of the total points was considered "good" quality (low risk of bias), of which 75% and 43% were "fair" (moderate risk of bias), and articles that are 43% or below are considered "poor" quality (high risk of bias).

Clinical trials were evaluated using Risk of Bias 2 (RoB 2) from Cochrane (Appendices 6, 7) [11]. Ratings for each domain ranged from “low”, “some concerns” to “high”. A study that had all its domains rated "low" was considered "low risk of bias", if at least one domain was rated "some concerns" and none of them were "high", it was considered "some concerns" (moderate risk of bias), and if at least one domain is rated as "high" or the majority of domains are rated as "some concerns", it was considered "high risk of bias".

Results

A total of 661 articles resulted from the database search. Of these, 122 were duplicates and excluded. The remaining 539 articles are screened and finally, 90 articles were included in the final analysis. The PRISMA flow diagram is presented in Figure 1. Among the included 90 articles, there were 40 in vitro studies, 26 in vivo studies, 18 studies that were both in vivo and in vitro, three clinical trials, two case reports, and one retrospective study.

Figure 1. PRISMA flow diagram of study selection.

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PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analysis; WHO GHL: World Health Organization Global Health Library; SIGLE: System for Information on Grey Literature in Europe; VHL: Virtual Health Library

Activities Against Cancer

G. lucidum spores have a variety of activities in fighting against cancer. The long-chain fatty acids in ethanol extract from G. lucidum spores show cell proliferation inhibitory in vitro on HL-60 cells [12,13]. The ethanol extract of G. lucidum spores has a stronger inhibitory activity on HUC-PC and MCT-11 cells in vitro than the aqueous extract [14]. Alcohol extract of G. lucidum spores can inhibit human breast cancer cells (MDA-MB231) [15], non-small cell lung cancer (NCI-H460), colorectal adenocarcinoma (HCT-15) [16], and human leukemia THP-1 in vitro [17]. Triterpenoid extract from G. lucidum spores showed activities against cervical cancer Hela cells [18]. Spores of G. lucidum also suppress invasion of breast cancer MDA-MB-231 and prostate PC-3 cells by inhibiting transcription factors [19,20]. G. lucidum spore extract show antitumor-mediated and immunomodulatory ability to significantly reduce PD-1 protein in B lymphocytes [21].

Studies showed that sporoderm-broken spores of G. lucidum (BSG) show excellent fighting capacity against cancer in vitro and in vivo. In an experimental mouse, oral administration of BSG (2, 4, and 8 g/kg per day) was able to significantly impede the growth of sarcoma S180, hepatoma, and reticulocyte sarcoma L-II cells. Tumor weight was significantly reduced by 14.1, 18.,5, and 16.6% compared with the control group [22]. In mice models inoculated with 4T1-breast cancer, treatment with BSG (400 mg/kg) showed a significantly lower tumor weight compared with the control group (387 ± 23 mg vs. 512 ± 45 mg, p < 0.05) [23]. Water extract of BSG (BSGWE) was seen to inhibit many cancer cell lines in vitro such as human osteosarcoma (HOS, U2, MG63) [24,25], murine osteosarcoma (K7M2) [24], human colorectal cancer (HCT116, HT-29) [26,27], murine metastatic breast cancer (4T1) [23,28], murine sarcoma 180 (S180) [29], HeLa [30,31], human CCA TFK-1 [32], and hepatocellular carcinoma (H22) [33].

In in vivo study, treatment of 0.5 mg BSGWE for four weeks significantly reduced tumor weight and volume of K7M2 cells transplanted into mice [24]. In a mouse model inoculated with HOS stably transfected cells into the tibia, treatment with BSGWE 600 mg/kg for 21 days significantly reduced tumor weight and volume (p < 0.01) [25]. In a HCT116 xenograft mouse model, six weeks of oral treatment with BSGWE inhibited tumor growth, tumor volume was reduced by 23.8 (dose of 150 mg/kg) and 47.8% (dose of 300 mg/kg), respectively (p < 0.05). The final tumor weight at surgery at both doses was significantly lower compared with the control group; 1.27 ± 0.19 g (150 mg/kg) and 1.00 ± 0.21 g (300 mg/kg) (p < 0.05 for both), respectively, in comparision with 2.22 ± 0.11 g (control) and 1.28 ± 0.23 g (treated with 5-FU) [26]. In an HT-29 xenograft mouse model, treatment with polysaccharide extracted from BSG (BSGP) (300 mg/kg) significantly reduced tumor mass and volume compared with the control group [27]. BSGP showed significant inhibition of S180 and 4T1 breast cancer growth in mice. In a mouse model inoculated with S180 cancer cells, 14 days of treatment with BSGP (100 and 200 mg/kg) significantly reduced tumor weight compared with the control group (physiological saline) (p < 0.05 and p < 0.01); inhibitor ratio was 49.1 and 59.9%, respectively [29]. Treatment with BSGP (10 mg/kg, 30 mg/kg, 100 mg/kg) for 21 days resulted in tumor weights (0.84 ± 0.32 g, 0.82 ± 0.34 g, 0.86 ± 0.16 g, respectively) compared with 1.45 ± 0.24 g in the control group (p < 0.01), while the tumor weight in cyclophosphamide (CTX) -treated group (30 mg/kg) was 0.88 ± 0.40 g [34]. Moreover, BSGP (200 mg/kg and 400 mg/kg) showed excellent effect when the tumor weight was lower than the group treated with paclitaxel (PTX), and significantly lower compared with the control group (p < 0.05) [28].

Ethanol extracts of BSG (BSGEE) significantly inhibited HCT116 cell proliferation in vitro (p < 0.01) in nude mice through multiple mechanisms [35]. The mean weights of tumor were 0.86 ± 0.28 (model group), 0.59 ± 0.20 (75 mg/kg), and 0.38 ± 0.23 g (150 mg/kg) (p < 0.05) [35]. A study examining the anti-tumor activity of BSGEE and ethanol/aqueous extract of BSG (BSGEA) showed that BSGEE inhibited the growth of all three lung cancer cell lines (A549, H441, and H661) with an IC50 of 150 µg/ml while BSGEA did not show efficacy up to 1000 µg/ml [36]. In the xenograft mouse model with human lung cancer A549 cells, treatment with BSGEE (200 mg/kg per day) for four weeks showed a mean tumor volume reduction of 39.35% compared with the control group (p < 0.05). The average tumor weight was 0.90 g in BSGEE-treated mice compared with 1.54 g in control mice (p < 0.05) [36].

A study comparing the anti-tumor activity of BSG and G. lucidum sporoderm-nonbroken (NBSG) showed that the purity of BSG was more active than that of NBSG against cancer cells including SGC-7901, HeLa [37]. In a mouse model subcutaneously implanted with mouse S-180, treatment of 2 g/kg BSG and NBSG showed a 31.5% and 22.4% reduction in tumor weight, respectively, compared with untreated controls [38]. Two kinds of G. lucidum spore powder, BSG and sporoderm-removed G. lucidum (RSG) were compared in vivo andin vitro antitumor activities. The results showed that RSG exhibited stronger tumor suppressor activities than BSG in in vitro, and in the zebrafish model, the inhibition rate on gastric cancer cell SGC-7901, lung cancer cell A549, and B lymphocyte cell line Ramos of RSG was 78%, 31%, and 83%, respectively [39]. RSG also showed greater inhibition of three types of human gastric cancer cell lines (MKN28, AGS, NCI‑N87) than BSG [40].

G. lucidum oil, lipid substance extracted from the G. lucidum spore, also showed strong anti-tumor activity. In in vitro, G. lucidum oil inhibited human acute myeloid leukemia cell (HL-60), human chronic myeloid leukemia cell (K562), human gastric carcinoma cell (SGC7901) [41], human breast carcinoma cell (MDA-MB-231) [42], and miR-378M cell [43]. In in vivo, G. lucidum oil (1.2 g/kg) significantly suppressed the growth of murine sarcoma (S180) and murine hepatoma (H22) transplant tumors. The inhibitory rate was 30.9% (p < 0.05) and 44.9% (p < 0.01), respectively [41]. G. lucidum oil (6 g/kg) once daily orally in mice significantly reduced tumor volume of 4T1-breast cancer after 21 days (p < 0.05); there was no significantly different from PTX (10 mg/kg twice weekly) [42]. Notably, G. lucidum oil nanosystems showed better antitumor activity against human gastric cancer cells (MGC803) than G. lucidum oil, due to improved absorption efficiency and cell storage of G. lucidum oil nanosystems. In mice, treatment with G. lucidum oil 40 nm-nanosystems for 22 days reduced the tumor volume from 891 mm³ to 286 mm³, a therapeutic effect similar to CTX (40 mg/kg) [44].

Treatment with G. lucidum spore in gynecological cancer patients showed stable disease status in three out of six cases, while in the placebo group, all patients showed progressive disease [45]. Administration of G. lucidum spore twice daily in five cases of gastric cancer showed increased serum levels of tumor marker, CA72-4 [46]. A clinical study of 48 breast cancer patients showed that administration of G. lucidum spore powder (1000 mg three times daily) for four weeks resulted in significant improvements in areas of physical, reducing anxiety and improving the quality of life. Immune parameters such as tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) were also improved [47].

Immunomodulatory Activities of G. lucidum Spores

The polysaccharides of G. lucidum spores (SGP) were the most reported components of immunological activity. β-D-(1→3)-glucan SGP at concentrations of 1-100 µg/mL displayed a dose-dependent T lymphocyte-stimulating activity induced by concanavalin A [48]. The carboxymethylated derivatives of polysaccharides (1 or 100 µg/mL) also enhanced the proliferation of T and B lymphocyte, as it will be decreased as the level of substitution increased. Substitute compounds with lower levels seem to be more active than higher ones [49]. SGP showed a dose-dependent stimulation of lymphocyte proliferation in mice induced by concanavalin A and lipopolysaccharide [50].

G. lucidum mycelium extract induced human peripheral blood mononuclear cell (PBMC) and monocyte proliferation, while in contrast, G. lucidum spore extract suppressed PBMCs [51]. In addition, SGP significantly suppressed the proliferation of T cell in the association with increased IL-10 production [52]. For splenic mononuclear cells, treatment with SGP (at concentrations of 200, 400, and 800 mg/ml) significantly increased the proliferation of mononuclear cells and increased cytokine production (IL-2, TNF-α) [53]. In another study, microwave-treated SGP also significantly stimulated the secretion of cytokine production (TNF-α, IL-6) [54]. Extracts of G. lucidum spores (40 mg/ml and 80 mg/ml) significantly enhanced the function of human polymorphonuclear neutrophils (PMNs) (both p < 0.05). Extracts of G. lucidum spores may have modulated human immunity through the p38 mitogen-activated protein kinase pathway [55].

The immunological activity of G. lucidum spores has also been tested in animals. Especially, β-D-glucan as an immunostimulator has attracted much attention because it is beneficial for the treatment of cancers. β-D-(1→3)-glucan (dose of 25 or 50 mg/kg) for four successive days in mice showed an enhancing effect on T lymphocyte proliferation, significantly different from the control group [48]. The carboxymethylated α-D-(1→3)-glucan (dose of 25 or 50 mg/kg) also substantially enhanced the proliferation of T and B lymphocyte [49]. The native glucan, named PGL (doses of 25 mg/kg and 50mg/kg) had a strong effect on suppressing the antibody production in mice (p < 0.05). And the effect at a higher dose of 50 mg/kg was stronger than that at a lower dose of 25 mg/kg [56]. The degraded glucan showed a greater ability to increase T and B lymphocyte proliferation and production of antibodies against sheep red blood cells in mice than native glucan [57]. Intraperitoneal treatment of SGP (dose of 50, 100, 200 mg/kg) for 10 days significantly increased the concanavalin A-induced proliferative response of splenocytes. In addition, two-week transperitoneal SGP showed dose-dependent inhibitory activities on tumor growth of Lewis lung cancer in C57BL/6 mice [54].

Crude SGP and refined SGP have shown activity in the immune system of BALB/c mice. Crude polysaccharide and refined polysaccharide treatment for 30 days suppressed mitogen-induced splenocyte proliferation (concanavalin A or lipopolysaccharide) (p < 0.05). Interestingly, tumor-killing ability of NK cells was significantly promoted by crude polysaccharides (p < 0.01) but not refined polysaccharides while only refined polysaccharides promoted the activation of T cells [58]. Meanwhile, GLSB70 and GLSB50, two polysaccharide fractions obtained from aqueous extracts of NBSG can stimulate humoral immunity in mice immunosuppressed with CTX. GLSB50 and GLSB70 (300 mg/kg per day) showed extremely significant increases in HC50 values (serum half-hemolytic values) (p < 0.01 and 0.05, respectively). GLSB50 exhibited better and comparable activity to the positive control lentinan [59]. In another study, NK cell cytotoxicity and macrophage phagocytosis were also significantly enhanced by the lipid fraction, and G. lucidum oil (800 mg/kg). G. lucidum oil showed immune-enhancing effects on both innate and cellular immunity and significantly increased the intestinal Bacteroidetes/Firmicutes ratio [60].

BSG and RSG showed immunological activity in the zebrafish model as significantly improved neutrophils (p < 0.05 or 0.01) after 24 h, RSG exhibited greater activity. Moreover, only RSG was able to significantly promote macrophage formation (p < 0.01) [61]. In mice, β-glucan from BSG (dose of 75, 150, 300 mg/kg) could promote dinitrochlorobenzene to delayed ear swelling similar lentinan (150 mg/kg) [62]. CTX-induced immune suppression and SGP can counteract CTX toxicity and restore the immune system. In mice treated with SGP (50 mg/kg/day) thymus weight was significantly higher than in mice treated with CTX alone (p < 0.05) [63].

A randomized controlled double-blind trial in postoperative patients with breast and lung cancer showed that treatment with G. lucidum spore powder (2000 mg, twice daily for six weeks) increased CD3+ CD4+ CD3+ HLADR- cell types, whereas decreased CD4+ CD25+ Treg, CD3+ HLADR+ cell types compared to control [64].

Anti-inflammatory of G. lucidum Spores

In vitro study that simulates digestion has shown that RSG can promote the release of the active ingredient more readily than other forms of G. lucidum spores so that the active ingredients are more easily absorbed. In particular, BSGWE has the best anti-inflammatory effect on the intestines [65].

BSGP significantly reduced the expressions of pro-inflammatory cytokines in mice fed with a high-fat diet. BSGP also had gut microbiota modulating activities (increased Allobaculum, Bifidobacterium, and decreased Lachnospiraceae_UCG-001, Ruminiclostrdium) [66]. Besides, pretreatment with a high dose of G. lucidum spores (1 g/kg per day) can relieve symptoms of sialoadenitis in non-obese diabetic mice [67].

Antioxygenation Activity of G. lucidum Spores and Reduction of Oxidative Stress

The radical scavenging activity of G. lucidum spore increased as the concentration increased. The percentage inhibition of 1,1-diphenyl-2-picrylhydrazyl (DPPH)radical of triterpenoids was 62.16% at 400 µg/ml [68]. In another study, the percentage inhibition of DPPH radical of triterpenoids (600 μg/ml) reached a maximum (61.09 ± 1.38%) [18]. A novel natural proteoglycan from BSG and NBSG also showed antioxidant activity with DPPH scavenging activity of 90.6 ± 8.5% and 72.6 ± 3.7%, and with ABTS scavenging effect of 73.3 ± 6.7% and 47.2 ± 5.9%, respectively [31].

The breaking techniques and extraction solvent for G. lucidum spores may affect free radical scavenging activity. Among the reported methods, maceration with spheres of various materials extract contained the most significant antioxidant activity, with 57.22 ± 0.09% [69]. Phenolic and polysaccharide extracts also showed different antioxidant capacities [70].

In the reducing power assay, G. lucidum spore powder revealed high antioxidant activity, the reducing power of G. lucidum spore powder increased with an increase in drying temperature (from 95°C to 105°C), in some cases even higher than the antioxidant property of ascorbic acid [71].

In a rabbit ischemia/reperfusion (I/R) model, pretreatment with BSG was shown to minimize damage, inhibiting the negative effects of I/R on both response compliance. That mean BSG can reduce oxidative stress [72]. In the Drosophila melanogaster model, the G. lucidum oil-treated groups had mean and maximum lifespans significantly longer than untreated groups, under both normal and oxidative stress conditions. G. lucidum oil treatment markedly affected the activity of antioxidant enzymes such as increasing total superoxide dismutase and catalase activities and decreasing malondialdehyde levels [73].

Protective Activity of G. lucidum Spores

Studies showed that G. lucidum spores or extracts of G. lucidum spores have protective capabilities such as retinal protection [74], cardiac protection [75-77], hepatic protection [78], intestinal protection [79], neuroprotective effect [80], bone marrow cells protection [81] and efficiency on apoptosis [74,79,82].

Organ protection against apoptosis by pre-treatment with G. lucidum spores has been observed in in vivo studies. Pre-treatment with G. lucidum spores (50, 100, 150 mg/mL, for 19 days) showed a dose-dependent reduction in the splenic index and significantly different apoptosis compared with the model group (p < 0.05) [82]. G. lucidum spore lipid administration inhibited N-methyl-N-nitrosourea-induced retinal photoreceptor apoptosis in vivo (p < 0.01 on days 1 and 3) [74]. SGP shows promising protective activities against PTX-induced small intestinal barrier injury by inhibiting apoptosis, and promoting small intestinal cells’ proliferation [79].

Pre-treated G. lucidum spore oil (5mL, @P188/PEG400) nanosystem four to eight hours before X-ray irradiation protected H9C2 cells from X-rays (16 Gy) (cell viability of H9C2 cells increased to 101.4-112.3%. Moreover, treatment with G. lucidum spore oil (5mL, @P188/PEG400) nanosystem in mice significantly reduced X-ray-induced necrosis [75]. G. lucidum extracts also increased heart function [76,77].

In a mice model of cadmium chloride (CdCl2)-induced hepatotoxicity (3.7 mg Cd (II)/kg, i.p.), seven days of pre-treatment with G. lucidum spore reduced liver enzymes (Alanine transaminase (ALT), aspartate aminotransferase (AST)) and liver weight/body weight ratio [78]. In the nervous system, pre-treatment with a high dose of G. lucidum spores (8 g/kg) was shown to help protect neurons from apoptosis, and ameliorate cognitive dysfunction in rats undergoing intracerebroventricular injection of streptozotocin procedure [80]. In vivo trials in mice showed that G. lucidum spores could protect bone marrow mesenchymal stem cell and promote hematopoiesis recovery in CTX-treated [81].

Antimicrobial Activities of G. lucidum Spore

The aqueous extract of G. lucidum spore had antibacterial properties against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Klebsiella pneumoniae (minimal inhibitory concentration (MIC) of 125 mcg/ml, 125 mcg /ml, less than 02 mcg/ml, and 62.5 mcg/ml, respectively [83]. The Mann‐Whitney U test and Chi‐square test showed that there was no significant difference between the antibacterial effect of mycelium and spores against P. intermedia and that both mycelium and spores were effective (MIC of 5.64 and 3.62 mcg/ml, respectively [84]. Besides, topical application of G. lucidum spore powder or aqueous or organic solvents also showed antibacterial effects [85].

The antibacterial effect against S. aureus, E. coli was also tested with different extracts from G. lucidum spores. The extracted triterpenoids showed that the diameter of the inhibition zone for both bacteria was significant [18]. Chitosan from G. lucidum spore powder obtained through both thermal deoxidation, (TCD) and emerging ultrasonic-assisted deoxidation (USAD) also displayed enhancement of antibacterial zone against both E. coli and S. aureus, USAD extraction showed higher activity [86]. A novel natural proteoglycan from cracked (proteoglycan-C) and uncracked G. lucidum spore powder (proteoglycan-UC) also showed activity against these two bacteria [31].

The antibacterial activity of BSG and spores lipid was tested in a mice model against infection with Mycobacterium tuberculosis. The mean bacterial load at week 24 was approximately 2.5 log10 CFU in the lungs, and more than 4 log10 CFU in the spleen, showing significant statistical difference compared to the control group [87].

Metabolism and G. lucidum Spore

G. lucidum spore and its extraction are considered to be potential in hypoglycemic and hypolipidemic activities. These activities were presented by blood glucose level [88-90], glycated hemoglobin (HbA1c) [89] and blood total cholesterol (TC), triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels [78,88-91].

In glycemic metabolism, in vitro studies show that G. lucidum spore powder extracts such as triterpenoids or proteoglycan can modulate insulin sensitivity in insulin-resistant HepG2 cells and reduce glucose concentration [31,68]; moreover, oligosaccharide of G. lucidum spore can be considered to use as an effective prebiotic [92]. In in vivo studies, treatment with resistant starch spores (10.5 g/kg bw/day) in diabetic rats reduced blood glucose level by 21.9% in week 3, and it was also significantly lower than the model group (p < 0.05) [88]. In the streptozotocin (STZ)-induced diabetic rats model, there was a significant reduction in blood glucose in the G. lucidum spores group compared with the STZ group (23.98 ± 5.20 mmol/L vs 30.08 ± 3.13 mmol/L, p < 0.05). HbA1c decreased by 6% in the G. lucidum spores group compared with the STZ group (but no significant difference) [89]. Treatment of G. lucidum spore powder in diabetic rats for four weeks also decreased blood glucose levels (p < 0.05). Blood glucose levels in the intervention group and model group were 24.31 ± 1.17 mmol/L and 32.22 ± 1.71 mmol/L, respectively [90]. In addition, by the effect of G. lucidum spore and BSGEE [91] or SGP [89,90]), the HDL-C value in the intervention group increased [88,91], and reduced serum level of TG, TC, and LDL-C [89,91]. Moreover, G. lucidum spore powder significantly inhibited body weight from increasing under a high-fat diet. G. lucidum spore powder may tend to reduce serum TG while it had no effects on HDL [66].

Efficiency on Alzheimer’s Disease

In the Morris water maze, RSG (360 and 720 mg/kg) ameliorated amyloid β (Aβ) deposition and Tau phosphorylation, and prevented the reductions of neurotrophin brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase B receptor in the hippocampus in sporadic Alzheimer’s disease rats. Therefore, BSG enhanced memory and showed potential for the prevention and treatment of Alzheimer’s disease [93].

Wound-healing Activity of G. lucidum Spore

Skin wound healing assay performed on mice showed using G. lucidum oil increased collagen deposition in skin burn injury. Moreover, G. lucidum oil significantly accelerated skin wound healing and reduced levels of inflammatory cytokines [94].

Induction of Proliferator-activated Receptor Alpha Activity

Based on fold induction data, it is found that G. lucidum spore lipid potently and selectively induced the activity of PPARα. As a result, G. lucidum spore lipid may be the potential the in treatment of many diseases such as hyperlipidemia, modulating the immune reaction specifically, suppressing chronic inflammation [95].

Proliferation Enhancers

Ganoderma spores extract at 0.01% and 0.1% (wt/vol) significantly promoted embryonic stem cell growth (p < 0.05) [96].

Epilepsy Treatment

In vitro experiments showed the antiepileptic activity of G. lucidum spore. The expression of NT-4 in G. lucidum spore group was higher than model group (p > 0.01), and at 0.122 mg/ml concentration G. lucidum spore for best effects [97]. Ganoderic acids from G. lucidum also showed antiepileptic potential based on the evaluation of apoptosis, and BDNF and TRPC3 expression, especially at 80 μg/ml [98]. A retrospective study of 18 patients with epilepsy showed that using G. lucidum spore reduced the weekly seizure frequency from 3.1 ± 0.8 to 2.4 ± 1.2 (p = 0.04) [99].

Anti-aging Activity of G. lucidum Spore

The anti-aging effect of ganodermasides A and ganodermasides B from G. lucidum spores was shown through upregulation of UTH1 expression and extending the replicative life span of yeast [100].

The pharmacological activities of G. lucidum spore are listed in Table