Anti-Diabetic, Anti-Inflammatory and Antioxidant Properties of Four Underutilized Ethnomedicinal Plants: An in Vitro Approach

Abstract Background : In the present study, antidiabetic, anti-inflammatory activities and antioxidant properties in four diverse dissolvable concentrates of four lesser known ethnomedicinal plants viz. Apluda mutica, Mikania micrantha, Kyllinga nemoralis and Cleome rutidosperma were investigated. Methods: The benzene, chloroform, methanol and 70% aqueous (aq.) ethanol extract of these plants were tried for antioxidant by various established in vitro systems like total phenolic content, DPPH free radical scavenging, ABTS radical cation scavenging, metal chelating activity. Anti-diabetic and anti-inflammatory activities were explored by quantifying α-amylase, α-glucosidase and protein denaturation inhibitory activities of the investigated plants. Results: Among the various solvents 70% aq. ethanol extract of M. micrantha had the highest total phenolic content (230.450 ± 0.12mg GAE/g extract), DPPH & ABTS radical scavenging activity, FRAP value (4.122± 0.004 μM Trolox equivalent/ g dry extract), anti-lipid peroxidation capacity, reducing power and metal chelating activity. The highest amount of total flavonoid was detected in the 70% aq. ethanol extract of C. rutidosprema (71.050 ± 0.058 mg RE /g extract. Similarly M. micrantha also exhibited significantly lower IC 50 values for the percentage inhibition of α-amylase (IC50 58.44 ± 0.012 µg/ml) and α-glucosidase (IC50 113.31 ± 0.010 µg/ml) compared to acarbose (IC50 = 53.8 ± 0.009 µg/ml ; IC50 = 79.48 ± 0.006 µg/ml respectively) (p ≤ 0.05). Anti-inflammatory activity was determined by using protein denaturation assay and M. micrantha showed significant lower IC50 value for the inhibition of protein denaturation (IC50= 89.27 ± 0.008 µg/ml) compared to other plants under investigation. Quantification of polyphenolics by HPLC showed the presence of different phenolic acids in varying amounts. Conclusion: Therefore, the results indicate that these plants were shown to contain a remarkable amount of different bio-active compounds, thus confirming their involvement in several biological activities and to serve as a potential antioxidative, anti-inflammatory and anti-diabetic agent in food and pharmaceutical industries.