Isolation of curcumin from Lakadong turmeric of Meghalaya and development of its PLGA-Cur-NS loaded nanogel for potential anti-inflammatory and cutaneous wound healing activity in Wistar rats

Abstract

Abstract Background Lakadong turmeric (LKD) from Meghalaya, India, boasts high curcumin levels, but lacks scientific study. Moreover, Curcumin's poor solubility hinders its clinical use in inflammation and wound healing. This study isolated curcumin from LKD, forming a PLGA nanosuspension-based nanogel and explored for its potential anti-inflammatory and cutaneous wound healing activity in Wistar rats. Methodology The LKD rhizome was successively extracted by soxhlet using chloroform, hexane, ethyl acetate and methanol and their total phenolic content and antioxidant property was determined. Chloroform extract was loaded in column chromatography and curcumin was isolated, purified and characterized by FTIR, NMR, DSC, MS and HPTLC and its purity was analyzed by HPLC. The isolated curcumin was loaded into PLGA nanosuspensions by nanoprecipitation method followed by conversion to carbopol based Nanogel. The nanogels were characterized physicochemically and the drug permeation was observed. The optimized nanogel was evaluated for its anti-inflammatory and cutaneous wound healing activity by carrageenan-induced paw edema and excision wound model in albino Wistar rats divided in five groups and treated with plain carbopol gel, marketed turmeric cream and Cur NS nanogel (0.6% w/w equivalent curcumin each). Results Results depicted that the chloroform extract showed the presence of a considerable amount of phenolics with 50-60% yield of curcumin. HPLC analysis depicted that the LKD curcumin had higher purity when compared to standard curcumin. Homogenous curcumin nanosuspensions were obtained with size 150 ± 50 nm and PDI 0.2 ± 0.1. The Cur-NS-nanogel showed satisfactory physical property, drug loading and stability. Ex vivo permeation studies in rats showed controlled permeation with steady state flux of 21.28 ± 0.23 µg/cm2/hr in 24 h. Topical intervention with Cur-NS-nanogel (0.6%) significantly (p < 0.05) decreased the paw volume by 43.97% in the 3rd hour and 72.19% on the 4th hour. Furthermore, the cutaneous wound healing property of Cur-NS-nanogel when compared to negative control rats showed a substantial (p < 0.05) reduction in the percentage wound contraction from 5 to 20th days. Conclusion LKD showed high curcumin content with significant antioxidant effects. LKD curcumin loaded into stable nanogel depicted safe and controlled skin permeability with promising cutaneous wound healing and anti-inflammatory activity in experimental rats.