Ganoderma lucidum is a popular herbal medicine utilized in China to promote health. Modern research has disclosed the active ingredients of Ganoderma can exhibit a number of effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared ganoderma lucidum spore oil and spores oil, and investigated the potential underlying mechanisms by observing the results of the extracts and oil on topoisomerases and also the cell cycle. The results showed that Ganoderma extracts and spores oil presented dose-dependent inhibitory effects on tumor cells.
Ganoderma lucidum, also called Ganoderma or Lingzhi, is among most frequently used fungi in Chinese medicine. Modern pharmacological and scientific studies have confirmed that Ganoderma contains abundant biologically active substances in their fruiting body, mycelia and spores, and possesses variable functions, including immunomodulation, anti-aging, reducing blood lipids, anti-viral and anti-tumor activities (1-6). The current study examined the antitumor activity of a mixture of aqueous and ethanol extracts in the Ganoderma fruiting body and Ganoderma spores oil, which was extracted from broken spores by supercritical CO2 extraction technology and explored the potential underlying mechanisms. DNA topoisomerases are a class of enzymes involved in the regulating DNA supercoiling.
Topoisomerase overexpression has become connected to a number of human malignancies and is also the target for numerous chemotherapeutic agents (7). When topoisomerases are blocked, the cell encounters problems during transcription of the DNA and throughout cell division. The widely-used antitumor drug, campothecin, blocks the relaxing action of class I topoisomerases and induces significant G1 cell cycle arrest (8). A previous study indicated that the active components of Ganoderma exhibited inhibition of topoisomerases (9). The present study examined whether Ganoderma extracts and spore oil affected the cell cycle and topoisomerases I and II.
Preparations of Ganoderma extracts and spores oil – Ganoderma extracts (GanoHerb™) and Ganoderma spores oil were supplied by Fujian Xianzhilou Biological Science and Technology Co., Ltd. (Fuzhou, China). Ganoderma extract, a brown powder, was dissolved in double distilled water to get ready solutions of various concentrations, which were brown suspensions. Ganoderma spores oil was a soft capsule with .5 g/.5 ml golden oil in each capsule. The stock solution of Coriolus Versicolor Extract were prepared using double distilled water that contained 6 µl/ml (v/v) Tween 80.
Recently, the effect of Ganoderma on tumors has been increasingly studied. The present study revealed that Ganoderma extracts and spores oil inhibited the growth of human leukemia cells (K562 and HL60) and human gastric carcinoma cells (SGC-7901) in a dose-dependent manner. Furthermore, Ganoderma extracts and spores significantly suppressed the growth of the S180 and H22 transplant tumors in mice. Therefore, Ganoderma extracts and spores oil demonstrated definite antitumor effects inside the in vitro vrlzqn in vivo studies.
Since olden days, Ganoderma has been widely used being a popular herbal medicine for that promotion of health (11). Numerous previous studies examined the immunomodulatory activities of Ganoderma (12,13). By detecting the immunity indexes of mice bearing S180 or H22 cells, Ganoderma extracts were concluded to possess a certain effect on improving immune function, while Ganoderma spores oil had no significant effect on the spleen or thymus indexes of mice. One of the main elements of Ganoderma extract is really a polysaccharide which has been reported as immune function enhancer (12-15). Because there were few polysaccharides (water-soluble substances) in the Ganoderma spores oil, the spores oil exhibited no evident effect on immunity. The current study also revealed that the antitumor results of Ganoderma could be safer compared with 5-FU, which led to the decreased body weight and immunity indexes of mice (Tables I and ?andIIII).
To investigate the potential mechanism of ganoderma lucidum spore powder, the effects of extracts and spores oil on topoisomerases as well as the effect of spores oil on the cell cycle were examined.
DNA topoisomerases are a class of enzymes active in the regulation of DNA supercoiling. Type I topoisomerases change the amount of supercoiling of DNA by causing single-strand breaks and religation, whereas type II topoisomerases cause double-strand breaks. Both of these activities are particularly crucial during DNA transcription and replication, once the DNA helix has to be unwound to permit proper function of large enzymatic machinery. Cancer chemotherapy uses this finding, using drugs that block topoisomerases to kill rapidly-dividing cancer cells. For instance, the widely-used anthracycline drugs, like doxorubicin and daunorubicin, attack class II topoisomerases and also the plant toxin, campothecin, blocks the relaxing action of class I topoisomerases.