In vivo Wound Healing Activity of the Methanolic Extract and its Isolated Constituent, Gulonic Acid γ-Lactone, Obtained from Grewia tiliaefolia

Grewia tiliaefolia is a subtropical tree, its stem bark is widely used in traditional Indian medicines to heal chronic wounds, gastric ulcers, burning sensation, itching and other allergic ailments. Bioassay-directed fractionation and chromatography of the methanolic extract of G. tiliaefolia stem bark has resulted in the isolation of gulonic acid gamma-lactone. The methanolic extract and the isolated constituent were studied for their potency on three different cutaneous wound models, viz., excision, incision and dead space wounds in Wistar rats. In the excision wound model, healing was assessed by the rate of wound contraction and period of epithelisation. In the incision wound model, the degree of healing was analysed by determining the skin breaking strength. In the dead space wound model, the parameters used to confirm the healing process were weight of granulation tissue, its tensile strength, hydroxyproline content and histological studies. The extract as well as the constituent demonstrated wound healing activity. Topical application of gulonic acid gamma-lactone (0.2% w/w ointment) caused faster epithelialisation with 94.02% wound contraction on day 16 post-wounding, while in control animals the duration of healing was extended up to 22 days with 79.53% wound contraction. The tensile strength of the incision wound was significantly increased (561.12 +/- 5.18g) compared to the control (327.63 +/- 6.37g). In the dead space wound model, a significant increase in weight, tensile strength and hydroxyproline content of the granuloma tissue was observed following oral administration of gulonic acid gamma-lactone (60 mg/kg). Histology of the granuloma tissue showed increased collagenation and the absence of monocytes. The wound healing effect was compared with that of the standard skin ointment nitrofurazone. The results of this investigation provide supportive scientific evidence for the medicinal use of G. tiliaefolia for healing of cutaneous