In vitro and in vivo antidiabetic activity of Polyalthia longifolia (Sonner.) Thw. leaves

Phytochemical profiling and nephroprotective potential of ethanolic leaf extract of Polyalthia longifolia against cisplatin-induced oxidative stress in rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Kidney problems are becoming more common globally and are considered a major health issue in the modern world with high mortality rate. Polyalthia longifolia (Sonn.) Thwaites is a tropical ethnomedicinal plant used to treat various diseases like diabetes, hypertension and urinary disorders and possess antioxidant and anti-inflammatory properties.

AIM OF THE STUDY

This study aimed to investigate the phytochemical composition of 70% ethanolic leaf extract of Polyalthia longifolia (Sonn.) Thwaites (PL) and evaluates its nephroprotective effects against cisplatin-induced nephrotoxicity in Wistar rats.

MATERIALS AND METHODS

The leaves of PL were extracted with 70% ethanol and performed the phytochemical profiling using Liquid Chromatography-Mass Spectrometry (LC-MS). The nephroprotective effect of PL leaf extract was evaluated at three doses (150, 300 and 600 mg/kg, p.o.) for 14 days against cisplatin toxicity (16 mg/kg, i.p., once) in male Wistar rats. Body and kidney weight indices, kidney function markers and lipid profile markers in serum, and oxidative stress markers in kidney tissue were performed along with the histopathological analysis of kidney.

RESULTS

The LC-MS chromatograph confirmed the presence of various phytocompounds include N-Methylhernagine (aporphine alkaloid), 4-Acetamidobutanoic acid (gamma amino acid) and choline, etc. in the PL leaf extract. Exposure of cisplatin (16 mg/kg, i.p., once only) to the animals significantly elevated the levels of kidney functional markers (i.e. serum urea, uric acid, creatinine) and the lipid markers (triglyceride and total cholesterol) in blood circulation with depletion of serum albumin which were reversed by the therapy of PL leaf extract (150, 300 and 600 mg/kg) in dose-dependent manner. The altered level of body and kidney weight in cisplatin treated group was also restored by the therapy. PL leaf extract effectively improved the antioxidant defense system of kidney at all doses by restoring the levels of tissue glutathione, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase with the dose-dependent reduction of lipid peroxidation against cisplatin-induced renal oxidative stress. The histopathological observations also showed the significant recovery in cellular morphology after PL treatment when compared to the cisplatin toxicity group. The highest dose 600 mg/kg of PL leaf extract showed more pronounced renal recovery (p < 0.001) followed by other two doses, which was similar to the silymarin treatment group (a reference drug) against nephrotoxicity.

CONCLUSION

The results of this study revealed the nephroprotective effects of PL leaves against cisplatin-induced nephrotoxicity by reversing the level of biochemical markers and mitigating oxidative stress as well as improving the architecture of renal tissues. This renal protection by PL might be due to the synergistic effect of its phytoconstituents and antioxidant efficacy.

Inhibition of α-Amylase, α-Glucosidase, and Lipase, Intestinal Glucose Absorption, and Antidiabetic Properties by Extracts of Erodium guttatum

Erodium guttatum is widely used in traditional medicine to treat various diseases, including diabetes. In this study, we evaluated in vitro inhibitory activity of extracts of E. guttatum on α-amylase, α-glucosidase, and lipase and then studied in vivo using different animal models. The results showed that the aqueous and alcoholic extracts of E. guttatum significantly inhibited digestive enzymes. The extracts of E. guttatum significantly reduced postprandial hyperglycemia after starch loading in normal rats. Additionally, extracts of E. guttatum significantly decrease the intestinal absorption of D-glucose. However, the methanolic extract of E. guttatum showed remarkable antidiabetic activity compared to the aqueous and ethanolic extracts of E. guttatum. In addition, the extracts significantly reduced blood sugar levels in albino mice and hematological and biochemical profiles. Therefore, the results of this study show that the extracts of E. guttatum have antidiabetic effects and could therefore be suggested in the management of type 2 diabetes.

An exopolysaccharide (EPS) from a Lactobacillus plantarum BR2 with potential benefits for making functional foods

A high molecular weight EPS of glucomannan nature was recovered and purified to get an yield of 2.8±0.5g/L from Lb. plantarum BR2 and it displayed potent antioxidant activity with 29.8% radical scavenging activity and 19% total antioxidant capacity. At 100µg/ml concentration, it is capable of inhibiting the alpha amylase activity by 10% and at 300µg/ml, it drastically inhibited the alpha-glucosidase activity by 67% which indicates its antidiabetic potential. More interestingly, at a concentration level of 0.1%, it reduced the cholesterol level by a margin of 45% in an in vitro assay. The sample didn't reveal any cytotoxicity against H9C2 normal cells indicating its potential for safe use as a food additive.