Context: The fruit of Terminalia chebula Retz. (Combretaceae) has been used for several therapeutic purposes in Thai folk medicines. Currently, the ethanol extracts containing antioxidant compounds have shown the ability to promote collagen synthesis.
Objective: This purpose of this work was to study the effects of the ethanol extract from T. chebula fruit on the inhibition of cutaneous photodamage.
Materials and methods: The viability of human skin fibroblasts after incubation with T. chebula at concentration 0.5-50 μg/mL for 24, 48 and 72 h was assessed by using sodium 3'-[(phenyl-amino)-carbonyl]-3,4,tetrazolium-bis(4-methoxy-6-notro)benzene-sulphonic acid hydrate (XTT). The levels of type I procollagen and matrix metalloproteinases (MMP)-1 and MMP-13 produced by UVB-irradiated fibroblasts were determined by ELISA. Skin thickness and collagen content caused by long-term UVB irradiation in male ICR mice were determined from haematoxylin and eosin stained tissue sections and spectrophotometric measurement of hydroxyproline.
Results: The extract (0.5-50 μg/mL) had no effect on cell viability or morphology of the human fibroblasts. In vitro studies showed that the T. chebula extract reduced the UVB-induced MMP-1 and MMP-13 expression, whereas an increased production of type I procollagen was observed. In a UVB-irradiated animal model, male ICR mice with hair shaved were chronically exposed to UVB which lead to epidermal thickness and loss of hydroxyproline. However, these effects were fully prevented by the topical application of the T. chebula ethanol extract.
Discussion and conclusion: These data suggested that the T. chebula ethanol fruit extract is an efficacious pharmaceutical protectant of skin against photodamage.
Keywords: Antiageing; antioxidant; matrix metalloproteinases; photodamaged; type I procollagen.