Restoration of electric footshock-induced immunosuppression in mice by Gynostemma pentaphyllum components

Triterpenoids from the genus Gynostemma: Chemistry and pharmacological activities

ETHNOPHARMACOLOGICAL RELEVANCE

G. pentaphyllum, also known as Jiao-Gu-Lan, has been used traditionally as folk remedies for many diseases, including diabetes mellitus, metabolic syndrome, aging, and neurodegenerative diseases in China and some countries in East and Southeast Asia. It is considered as an "immortality herb" in Guizhou Province, because it was consumed regularly by the elderly native inhabitants. Other species of the same genus Gynostemma such as G. longipes and G. laxum have been used as alternatives to G. pentaphyllum in ethno-medicine in Vietnam and other Asian countries.

AIM OF THE REVIEW

The review aims to summarize up-to-date study results on Gynostemma species, including traditional usage, phytochemical profile, pharmacological activities, and toxicological studies, in order to suggest future research orientation and therapeutic applications on acute and chronic diseases.

MATERIALS AND METHODS

The relevant literature on the genus Gynostemma was gathered from secondary databases (Web of Science and PubMed), books, and official websites. The latest literature cited in this review was published in February 2020.

RESULTS

The genus Gynostemma has been widely used in traditional medicine, mainly for treatment of diabetes, hypertension, obesity, and hepatosteatosis. To date, 328 dammarane-type saponins were isolated and structurally elucidated from Gynostemma species. Crude extracts, saponin-rich fractions (gypenosides), and pure compounds were reported to show a wide range of pharmacological activities in both in vitro and in vivo experiments. The most notable pharmacological effects were anti-cancer, cardioprotective, hepatoprotective, neuroprotective, anti-diabetic, anti-obesity, and anti-inflammatory activities. Toxicological studies were conducted only on G. pentaphyllum, showing that the plant extracts were relatively safe in both acute and long-term toxicity experiments at the given dosage while no toxicological studies were reported for the other species.

CONCLUSIONS

The review summarizes current studies on traditional uses, phytochemistry, biological properties, and toxicology of medicinal Gynostemma species. Till now, the majority of publications still focused only on G. pentaphyllum. However, the promising preliminary data of other Gynostemma species indicated the research potential of this genus, both in phytochemical and pharmacological aspects. Furthermore, clinical data are required to evaluate the efficacy and undesired effects of crude extracts, standard saponin fractions, and pure compounds prepared from Gynostemma medicinal plants.

Effect of Eucommia ulmoides Oliv., Gynostemma pentaphyllum (Thunb.) Makino, and Curcuma longa L. on Th1- and Th2-cytokine responses and human leukocyte antigen-DR expression in peripheral blood mononuclear cells of septic patients

ETHNOPHARMACOLOGICAL RELEVANCE

Many traditional Chinese medicines (TCM), such as Eucommia ulmoides Oliv., Gynostemma pentaphyllum (Thunb.) Makino, and Curcuma longa L., have been reported to have various immune-modulatory effects.

AIM OF THE STUDY

To determine the effects of extracts from these three TCM on type 1 T help (Th1)- and Th2-cytokine responses and human leukocyte antigen (HLA)-DR expression in peripheral blood mononuclear cells (PBMCs) obtained from septic patients.

MATERIALS AND METHODS

Lipopolysaccharide (LPS)-stimulated PBMCs of healthy controls and septic patients were cultured for 48 hs with or without 0.05/0.1 mg/ml of TCM extract. HLA-DR expression in monocytes was detected using flow cytofluorimetry. The interferon [IFN]-γ, tumor necrosis factor [TNF]-α, interleukin (IL)- 2, IL-5, IL-10, and IL-13 levels in supernatants were measured with a human enzyme-linked immunosorbent assay.

RESULTS

Treatment with either 0.05 or 0.1 mg/ml of C. longa L. extract significantly restored the percentage of HLA-DR-positive monocytes, which was decreased by LPS in control and patient groups. Treatment with 0.05 or 0.1 mg/ml E. ulmoides Oliv. and C.longa L. extract decreased IL-10 production from LPS-stimulated PBMCs of controls and patients. In patients with sepsis, C. longa L. extract decreased IL-10 production to a greater degree than did E. ulmoides Oliv extract. Although IFN-γ, TNF-α, or IL-13 productions from LPS-stimulated PBMCs were influenced by E. ulmoides Oliv., G. pentaphyllum (Thunb.) Makino, or C. longa L. in control or sepsis groups in this study, only the influence of IL-10 was consistent in both control and sepsis groups.

CONCLUSIONS

By enhancing monocyte HLA-DR expression and decreasing IL-10 production, C. longa L. might help restore inflammatory responses in septic patients to eradicate pathogens.

Transcriptome Sequencing of Gynostemma pentaphyllum to Identify Genes and Enzymes Involved in Triterpenoid Biosynthesis

G. pentaphyllum (Gynostemma pentaphyllum), a creeping herbaceous perennial with many important medicinal properties, is widely distributed in Asia. Gypenosides (triterpenoid saponins), the main effective components of G. pentaphyllum, are well studied. FPS (farnesyl pyrophosphate synthase), SS (squalene synthase), and SE (squalene epoxidase) are the main enzymes involved in the synthesis of triterpenoid saponins. Considering the important medicinal functions of G. pentaphyllum, it is necessary to investigate the transcriptomic information of G. pentaphyllum to facilitate future studies of transcriptional regulation. After sequencing G. pentaphyllum, we obtained 50,654,708 unigenes. Next, we used RPKM (reads per kilobases per million reads) to calculate expression of the unigenes and we performed comparison of our data to that contained in five common databases to annotate different aspects of the unigenes. Finally, we noticed that FPS, SS, and SE showed differential expression of enzymes in DESeq. Leaves showed the highest expression of FPS, SS, and SE relative to the other two tissues. Our research provides transcriptomic information of G. pentaphyllum in its natural environment and we found consistency in unigene expression, enzymes expression (FPS, SS, and SE), and the distribution of gypenosides content in G. pentaphyllum. Our results will enable future related studies of G. pentaphyllum.

Modified Aloe Polysaccharide Restores Chronic Stress-Induced Immunosuppression in Mice

Chronic stress generally experienced in our daily lives; is known to augment disease vulnerability by suppressing the host immune system. In the present study; the effect of modified Aloe polysaccharide (MAP) on chronic stress-induced immunosuppression was studied; this Aloe compound was characterized in our earlier study. Mice were orally administered with MAP for 24 days and exposed to electric foot shock (EFS; duration; 3 min; interval; 10 s; intensity; 2 mA) for 17 days. The stress-related immunosuppression and restorative effect of MAP were then analyzed by measuring various immunological parameters. MAP treatment alleviated lymphoid atrophy and body weight loss. The numbers of lymphocyte subsets were significantly normalized in MAP-treated mice. Oral administration of MAP also restored the proliferative activities of lymphocytes; ovalbumin (OVA)-specific T cell proliferation; antibody production; and the cell killing activity of cytotoxic T lymphocytes. In summary; oral administration of MAP ameliorated chronic EFS stress-induced immunosuppression.

Effects of long-term chronic stress on the lymphoid organs and blood leukocytes of the rat (Rattus norvegicus)

Exposure of adult female rats (Rattus norvegicus (Berkenhout,1769)) to restraint (1 h) and after a gap of 4 h to forced swimming exercise for 15 min daily for 12 weeks resulted in a significant decrease in (i) weight of the body and lymphoid organs (spleen, thymus, and axillary lymph node), (ii) counts of total leukocytes and their subpopulation (lymphocytes, neutrophils, monocytes, eosinophils, and basophils), and (iii) healthy cells of all lymphoid organs and a significant increase in the count of apoptotic cells in all the lymphoid organs. One month after cessation of exposure to stressors (recovery group), all the parameters did not significantly differ from stress-group rats. The results may indicate that either deleterious effects of long-term chronic exposure to stress are not reversible or the 4-week recovery period is not sufficient to restore normalcy.

Effects of polysaccharides from Gynostemma pentaphyllum (Thunb.), Makino on physical fatigue

BACKGROUND

Gynostemma pentaphyllum (Thunb.) Makino has been reported to have a wide range of health benefits in Chinese herbal medicines. Polysaccharides from Gynostemma pentaphyllum (PGP), has been identified as one of the active ingredients responsible for its biological activities. Although many pharmacological activities of PGP have received a great deal of attention, there is limited evidence for the anti-fatigue effects of PGP. The purpose of this study was to investigate the effects of polysaccharides from PGP on physical fatigue.

MATERIALS AND METHOD

The rats were divided into four groups, with 10 animals per group: control (C), group, low-treated (LT), group, medium-treated (MT), group, and high-treated (HT), group. The C group received distilled water, while LT, MT and HT groups were given various doses of PGP (100, 200, 400 mg/kg· d). After 30 days, forced swimming test was carried out in an acrylic plastic pool, then the exhaustive swimming time of rats and some biochemical parameters related to fatigue were measured. The data obtained showed that PGP could extend the exhaustive swimming time of the rats, as well as decrease the blood lactic acid (BLA), and blood urea nitrogen (BUN), concentrations, and increase the hemoglobin, liver glycogen and muscle glycogen concentrations.

RESULT

The data obtained showed that different doses of PGP could extend the exhaustive swimming time of the rats, as well as decrease the BLA and BUN concentrations, and increase the hemoglobin, liver glycogen and muscle glycogen concentrations, which suggests that PGP had significant anti-fatigue effects on rats.

CONCLUSION

PGP may be of use as a potential anti-fatigue agent, but there is a need for further research on long-term use in order to show its positive effects on physical fatigue.

Anxiolytic effects of herbal ethanol extract from Gynostemma pentaphyllum in mice after exposure to chronic stress

In this study, the effects of herbal ethanol extracts of Gynostemma pentaphyllum (GP-EX), on chronic electric footshock (EF) stress-induced anxiety disorders were investigated in mice, which were orally treated with GP-EX (30 mg/kg and 50 mg/kg) once a day for 14 days, followed by exposure to EF stress (2 mA, with an interval and duration of 10 s for 3 min). After the final exposure to EF stress, the elevated plus-maze and marble burying tests were performed, and the levels of dopamine and serotonin in the brain, the serum levels of corticosterone, and the expression of c-Fos in the paraventricular nuclei (PVN) were determined. Treatment with GP-EX (30 mg/kg and 50 mg/kg) significantly recovered the number of entries into open arms and time spent on open arms, which was reduced by chronic EF stress. GP-EX (30 mg/kg and 50 mg/kg) also reduced the number of marbles buried, which was increased by chronic EF stress. In addition, electric EF stress significantly decreased the levels of dopamine and serotonin in the brain, which was recovered by treatment with GP-EX (30 mg/kg and 50 mg/kg). The serum levels of corticosterone, which were markedly increased by chronic EF stress, were reduced by treatment with GP-EX (30 mg/kg and 50 mg/kg). Chronic EF stress-induced increases in c-Fos expression were also markedly reduced by GP-EX (30 mg/kg and 50 mg/kg) in the PVN. These results suggest that GP-EX shows anxiolytic functions, determined by the elevated plus-maze and marble burying tests, which are mediated by modulating the activity of dopamine and serotonin neurons as well as the expression of c-Fos in the brain, and the serum levels of corticosterone. Clinical trials of herbal GP-EX and its bioactive components need further investigation.