Evaluation of in vitro Anti-inflammatory Activity of Basella alba and Oxalis corniculata and Formulation of a Topical Gel.

Abstract

Background: Basella alba and Oxalis corniculata belong to the family Basellacea and Oxalidacea, respectively. They have a diverse array of natural phytochemicals which possess especially anti-inflammatory activities. Objectives: To investigate the in vitro anti-inflammatory effects of authenticated fresh leaves of Basella alba, dried whole plant of Oxalis corniculata, combined extracts of these plants, and develop a topical herbal gel formulation Methods: The study comprised the water extraction of fresh Basella alba leaves via sonication and centrifugation, alongside the methanolic extraction from Oxalis corniculata whole plant using maceration in 70% methanol. Anti-inflammatory effects were assessed using protein denaturation assay (PDA) and heat-induced hemolysis inhibition assay (HIHIA), with diclofenac sodium and phosphate buffer (pH 7.4) serving as positive and negative controls, respectively. Absorbances were measured spectrophotometrically at 540 and 660 nm in the HIHIA and PDA, respectively. A topical gel was formulated incorporating the two extracts (2% from each), carbopol 940, carboxymethylcellulose, and disodium EDTA. All the formulations were kept at room temperature for 30 days to evaluate the stability. Results: The PDA demonstrated a positive % inhibition of denaturation with increasing concentrations by B. alba (6.55% at 0.0625 mg/mL and 10.88% at 1 mg/mL), the combined extract (7.47% at 0.0625 mg/mL and 11.60% at 1 mg/mL), and diclofenac sodium (11.72% at 0.0625 mg/ml and 21.68% at 1 mg/mL), while O. corniculata exhibited better % inhibition at lower concentrations (3.94% at 0.0625 mg/mL) than at higher ones (3.94% at 1 mg/mL). All extracts and diclofenac sodium exhibited positive results for erythrocyte membrane stabilization, with O. corniculata showing superior stabilization at lower concentrations (17.63%, 15.61%, 13.01%, 12.17% at 0.0625, 0.125, 0.25 and 0.5 mg/mL, respectively) in contrast to higher ones; notably, at a dose of 1 mg/mL, B. alba (22.33%), the combined extract (14.43%), and O. corniculata (7.63%) displayed considerable membrane stabilization compared to the positive control, diclofenac (8.73%). However, the linearity of the graphs in these assays was inappropriate to calculate IC50 values. Formulated herbal gel was stable for 30 days.

Conclusion: Only the water extract of Basella alba and the combined extract showed improved anti-inflammatory properties with increasing concentration.