Triterpenoid saponins from the leaves and stems of Pericampylus glaucus and their insulin mimetic activities

During an attempt to discover insulin mimetics, thirteen new triterpenoid saponins (1-13), including three phytolaccagenic acids (1, 2, and 12) and ten serjanic acids (3-11 and 13), as aglycones were isolated from a 70% ethanol extract of leaves and stems from Pericampylus glaucus. The chemical structures of compounds 1-13 were determined through spectroscopic data analysis, including NMR, IR, and HRESIMS. All isolated compounds (1-13) were evaluated using 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-d-glucose (2-NBDG) as a fluorescent-tagged glucose probe to determine their stimulatory effects on glucose uptake in differentiated 3 T3-L1 adipocyte cells. Consequently, four compounds (4, 7, 11, and 12) exhibited stimulatory effects on glucose uptake.

in vitro

Acanthamoeba species are pathogenic protozoa which account for amoebic keratitis, conjunctivitis and granulomatous amoebic encephalitis. These amoebae form cysts which resist drugs and more effective acanthamoebicidal agents are needed. Medicinal plants could be useful in improving the current treatment strategies for Acanthamoeba infections. In the present study, we examined the amoebicidal effects of Pericampylus glaucus (Lam.) Merr., a medicinal plant used for the treatment of conjunctivitis in Malaysia. Pathogenic Acanthamoeba triangularis were isolated from environmental water samples and treated with different concentrations of fractions obtained from Pericampylus glaucus (Lam.) Merr. as well as main constituents for 24-72 h. Chlorhexidine was used as a reference drug. Ethanol fraction of stem showed significant (p < 0.05) inhibition of trophozoites survival. Betulinic acid and periglaucine A from this plant at 100 μg/mL inhibited more than 70% survival of both cysts and trophozoites. The calculated therapeutic index for betulinic acid and periglaucine A was 170 and 1.5 for trophozoites stage and 3.75 and 8.5 for cysts stage. The observed amoebicidal efficacies indicate the beneficial aspects of this plant in the treatment of Acanthamoeba infection. Periglaucine A could also be of value for the treatment of Acanthamoeba infection.

Activity of Pericampylus glaucus and periglaucine A in vitro against nasopharangeal carcinoma and anti-inflammatory activity

ETHNOPHARMACOLOGICAL RELEVANCE

Pericampylus glaucus is a climbing plant found across Asia and used in traditional medicine to treat a number of conditions including splenomegaly, fever, cough, laryngitis, pulmonary disease, asthma, headache, hair loss, snake bite, boar bite, factures, boils, tumours, tetanus, rheumatic pain, itches and eclampsia.

AIM OF THE STUDY

To test extracts of P. glaucus in a number of bioassays and determine the legitimacy of its traditional use.

MATERIALS AND METHODS

The stems, leaves, roots and fruits of P. glaucus were collected and extracted sequentially with hexane, chloroform and ethanol, respectively. The anti-inflammatory activity was assessed by testing the ability of the extracts to inhibit heat induced protein denaturation, stabilise human red blood cells under hypotonic stress and by testing the inhibitory activity of the extracts against cyclooxygenases 1 and 2. Cytotoxicity was tested using the human lung epithelial cell line MRC-5 and nasopharangeal carcinoma cell line HK1 in the MTT assay.

RESULTS

Many of the samples showed an ability to prevent heat induced protein denaturation, as well as prevent lysis of red blood cells. Most of the extracts demonstrated inhibitory activity towards both of the COX enzymes. The ethanol extracts tended to demonstrate greater toxicity than other extracts, with some of the other extracts significantly enhancing growth and metabolism of the cells.

CONCLUSION

The benefit of P. glaucus for the treatment of diseases related to inflammation and cancer was supported by the in vitro assays adopted in this study.