Topical application of serine proteases from Wrightia tinctoria R. Br. (Apocyanaceae) latex augments healing of experimentally induced excision wound in mice

Wrightia tinctoria R. Br. (Apocyanaceae) is a folk medicinal plant known to have immunomodulatory, anti-inflammatory and antihemorrhagic potential. Wrightia tinctoria latex is used for treatment of various clinical conditions including psoriasis, blisters, mouth ulcers, and extensively for topical application on fresh wounds to promote accelerated healing. To investigate the wound healing potential of Wrightia tinctoria latex proteases using a mouse model. Proteolytic activity of Wrightia tinctoria latex proteases (WTLP) was determined on various substrates (casein, gelatin and collagen (type-I and IV)). The thermal stability and the class of proteases present in WTLP were determined using heat treatment and specific protease inhibitors, respectively. Excision wound model in mice was used to evaluate the healing potential of WTLP application (twice daily, 10mg/kg). Neosporin, a standard drug, was used for comparison. The progression of healing was monitored using physical (wound contraction), biochemical (collagen content, catalase and MMP activity) and histological examinations. WTLP contains thermostable serine proteases, which are completely inhibited by PMSF. WTLP showed strong caseinolytic, gelatinolytic and collagenolytic activity. The excision wound healing rate upon WTLP treatment was significantly higher than (>2-fold) the control group (49% vs. 18%, ⁎⁎p