Bioassays of inflammation pathways from combination of moringa oleifera, capsaicin and menthol

Abstract

Moringa oleifera is a multi-purpose plant native to Africa and Asia. Many studies have shown the medicinal value of its edible leaves, pods and seeds in treating inflammation and various diseases. The leaf is the most investigated part of this plant for its rich secondary metabolites, vitamins and minerals and has been incorporated in various herbal-based products. Herbal-based formulation to treat the inflammation is popular in the market. However, the effectiveness of anti-inflammatory and antioxidant of M. oleifera leaves extract-based formulation with capsaicin and menthol has not been determined. Hence, this study was focused on determining the antiinflammatory and antioxidant potential of M. oleifera leaves extract-based formulation with a combination of capsaicin and menthol. In this study, methanolic extract of ovendried M. oleifera leaves (OME) produced the highest yield (38.49 ± 0.24%), total phenolic content (3.2182 ± 0.1144 mg GAE/g) and total flavonoid content (2.2017 ± 0.1168 mg QCE/g) with promising ferric reducing antioxidant power (FRAP) (5.8456 ± 0.2446 mM Fe2+) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging (88.90 ± 0.38%) activities compared to fresh leaves and ethanolic extracts. Hence, the OME of M. oleifera leaves was chosen as the main ingredient in the cream formulation. Four formulations were made with different concentrations of capsaicin (0.03, 0.075, 0.1 and 0.2%) and menthol (2.8, 2.9, 2.925 and 2.97%). F1 which had the highest capsaicin concentration showed the strongest antioxidant capacities among all the formulations. EC50 of F1 in FRAP and DPPH assays were 49.85 ± 0.17 mg/mL and 6.84 ± 0.08 mg/mL, respectively. Also, F1 had the most promising proteinase (IC50 = 2.16 ± 0.03%) and lipoxygenase inhibition activities. The results indicated that the combination of M. oleifera, capsaicin and menthol in F1 formulation was a more promising anti-inflammatory and antioxidant compared to herbal-based formulation alone due to the synergic effect of the mixture. HPLC analysis of capsaicin and GC determination of menthol gave retention times at around 4.7 and 5.6 minutes, respectively, by referring to the standard. In conclusion, the combination of OME of M. oleifera leaves with capsaicin and menthol has the potential to be used as a medicinal formulation to relieve inflammation conditions.