Evaluation of Anti-diabetic and Antihypertensive activity of Phoenix sylvestris (L.)Roxb leaves extract and quantification of biomarker Quercetin by HPTLC

Abstract Background : Phoenix sylvestris (L.) Roxb. a member of the Arecaceae family is native to India and Pakistan, has traditionally been used for abdominal distress, fever, unconsciousness, constipation, gonorrhea, heartburn. The medicinal value of leaves namely free radical scavenging activity, anti-diabetic and antihypertensive properties had been studied in the present work. P. sylvestris leaf extracts showed anti-diabetic and antihypertensive properties. Purpose : The present study aimed to evaluate the antihypertensive and anti-diabetic potential of methanolic and hydro-alcoholic leaf extracts of P. sylvestris in experimental models along with flavonoids and phenolic content determination. Materials and Methods : The active constituents in the leaf extracts were evaluated by HPTLC. In-vitro assays were used for assessing the activities, namely antioxidant activity by DPPH assay and superoxide scavenging assay, antihypertensive activity by angiotensin-converting enzyme assay and anti-diabetic activity by α-amylase inhibitory assay and α-glucosidase inhibitory assay. In-vivo efficacy studies using animal models were performed for antihypertensive activity and anti-diabetic activity using Fructose-induced hypertension and alloxan induced diabetic model. Results : Amongst various extracts, only methanolic and hydro-alcoholic extract exhibited antioxidant properties. Methanolic extract (PSLME) had the lowest IC50 value (IC50:4.29±0.67 µg/ml) followed by hydro-alcoholic extract (PSLHAE, IC50: 7.61±0.38µg/ml) and were selected for screening their antihypertensive and anti-diabetic activity. The in-vitro antihypertensive activity for PSLME (35.59 - 89.65 %) and PSLHAE (33.36 - 78.47%) was comparable to the control (45.62-91.69%), suggesting the antihypertensive properties of the plant extracts. Similarly, the in -vitro anti-hyperglycemic assays showed that PSLME (26.45-78.48 % α-amylase activity inhibition and 38.28-76.07 α-glucosidase activity inhibition) and PSLHAE (26.45-78.48 % α-amylase activity inhibition and 29.14-72.30 % α-glucosidase activity inhibition) had comparable anti-hyperglycemic activity in comparison to control (34.73-92.18 % α-amylase activity inhibition and 42.24-86.44% α-glucosidase activity inhibition). Conclusion : Methanolic extract (PSLME) and hydro-alcoholic extract (PSLHAE) showed antihypertensive and anti-diabetic activity in in-vivo studies without inducing toxicity.