In‐vitro antihistaminergic, anticholinergic, antioxidant and mast cell stabilizing effects of partially purified Labisia pumila leaf extract

Labisia pumila is a popular medicinal plant in Malaysia and has been used in the treatments of various health complications. In this study, the in vitro anti‐histaminergic and anti‐cholinergic antioxidant and mast cell stabilizing effect of Labisia pumila crude leaf extract and partially purified fractions were investigated on guinea pig ileum. HPLC profiling of the bioactive extract were also examined. The crude extract was extracted using dichloromethane and partially purified into five fractions (A‐E) using column chromatography. The in vitro anti‐histaminergic and anti‐cholinergic studies were examined using organ bath containing Krebs‐Henseleit solution (pH 7.4) gassed with 95% O 2 and 5% CO 2 and maintained at 37°C. Two concentrations of the crude and partially purified fractions (1×10 −6 g/ml and 1×10 −4 g/ml) were challenged against a range of doses of histamine (10 −6 – 10 −2 M) and acetylcholine (10 −8 ‐ 10 −2 M). Mast cell stabilizing effect was test using 0.5 ml subcutaneous injection horse serum along with 0.5ml of triple antigen containing 20000 million microorganisms. Determination of DPPH, TPC, hydroxyl, nitric oxide and superoxide radical‐scavenging activity was performed. HPLC analysis was performed using C18 column with 70% MEOH: 30%H 2 O as mobile phase and flow rate of 1 ml/min. The crude and partially purified fractions showed significant (p < 0.05) competitive dose‐dependent anti‐histaminergic and anti‐cholinergic, mast cell stabilizing and antioxidant activity. HPLC profiling revealed the presence of flavonoids (quercetin‐like, catechin‐like and kaempferol‐like compounds), alkaloids (berberine‐like compound), steroids, saponins, tannins and gallic acid‐like compound in the extract. Most of these phytochemicals have been reported to possess anti‐histaminergic, anti‐cholinergic, and antioxidant effects