Anti-hypertensive vasodilatory action of Gynura procumbens mediated by kaempferol 3-O-rutinoside

Abstract

Introduction: Gynura procumbens (GP), otherwise known as longevity spinach or “Sambung Nyawa” in Malay, is an evergreen herb found in Africa and Southeast Asian countries (including Brunei) used traditionally to treat various diseases such as fever, diabetes and hypertension. We examined GP’s vasodilatory action to determine its possible role via the cholinergic-mediated pathway. Methods: GP leaves were prepared by filtration and evaporation to obtain the aqueous (AEGP) and methanol (MEGP) extracts followed by screening for phytochemical constituents. The total phenol, total flavonoid and flavonol contents were determined using the corresponding Folin–Ciocalteau, and aluminium colorimetric methods and the presence of kaempferol 3-O-rutinoside in the extracts was detected using HPLC analysis. Organ bath studies were conducted to determine the vasodilatory activity using intact and denuded isolated rat aortic rings by exposure to either increasing concentration of extracts (0.25, 0.5, 1.0, and 2.0 mg/mL) or 10 µg/mL kaempferol 3-O-rutinoside in the presence or absence of acetylcholine (ACh) after pre-contraction by noradrenaline (NA). Results: MEGP contained more phytochemical constituents and higher content of total flavonoid and total flavonol but less phenolic content than AEGP. Furthermore, MEGP yielded a 20% elevated amount of kaempferol 3-O-rutinoside than AEGP. Both extracts significantly amplified ACh-endothelium dependent vasodilation and mediated relaxation at 1 mg/mL in endothelium-intact and endothelium-denuded aortic rings with MEGP as a more effective vasodilator than AEGP. Overall, these results imply the involvement of extracts in potentiating cholinergic pathway, which might be mediated by kaempferol, as shown by its vasorelaxation effects in endothelium-intact and –denuded aorta. Conclusions: The present findings demonstrate that the vasodilatory activities of the two Gynura procumbens extracts, AEGP and MEGP, in thoracic aorta rings isolated from rats are potentially mediated via a cholinergic pathway through the action of a flavonoid particularly kaempferol 3-O-rutinoside.

Comparative analysis of flavonoid metabolites from different parts of Hemerocallis citrina

“…Procyanidin B1 presents anti-inflammatory [49], antioxidant activity and anti-apoptotic effect [50]. As for the dominant flavonoid metabolites in flowers, Kaempferol-3-O-rutinoside has antiglycation [51], antihypertensive [52], and anti-cancer activity [53]. The distribution of dominant metabolites in different parts has complicated characteristics, indicating that the chemical or pharmacological components of plant parts have the potential for diversity [54].…”

IDENTIFIKASI METABOLIT SEKUNDER DAN UJI AKTIVITAS ANTIOKSIDAN DARI EKSTRAK DAUN SAMBUNG NYAWA (Gynura procumbens (Lour.) Merr).

“…Merr). Daun sambung nyawa banyak ditemukan di Afrika dan negara-negara tropis Asia seperti: Thailand, Malaysia, Cina dan Indonesia [2][3][4].…”