In vitro evaluation of anti-aging activity of Artocarpus lakoocha heartwood extract

Abstract

Artocarpus lakoocha heartwood extract, locally called Puag-Haad, and its main active constituent oxyresveratrol are known to be a potent tyrosinase inhibitor and antioxidant, given them promising potential for use in dermatological and cosmetic products. The primary objectives of this study were to evaluate Puag-Haad and oxyresveratrol for their anti-aging activities and relevant mechanisms based on several in vitro assays, including proliferative/cytotoxic effects on cultured fibroblasts and possible protection against oxidative stress (UV-A and hydrogen peroxide) - induced DNA and cell damages, as well as their anti-collagenase activity. The results were compared with commonly used antioxidants, i.e., epigallocatechin gallate (EGCG), French pine bark extract (pine bark), L-ascorbic acid and Trolox©. Puag-Haad and all other antioxidants were found to stimulate the fibroblast proliferation in a 25 – 50 μg/mL range based on the MTT assay. As the concentration was increased to 100 μg/mL, the proliferative effect slightly decreased and became cytotoxic at 250 μg/mL for all antioxidants except for pine bark and Trolox©. All the test antioxidants were also capable of similarly protecting the fibroblasts against H₂O₂-induced cell damages at all studied concentrations (25, 50 and 100 μg/mL) except for L-ascorbic acid which could provide protection only at 25 μg/mL. Regarding the protection against UV-A radiation, L-ascorbic acid was the most effective, providing significant protection at all concentrations (25, 50 and 100 μg/mL), whereas Puag-Haad and other antioxidants similarly provided partial protection mainly at 100 μg/mL. Evaluation of fibroblast membrane irritation based on the LDH assay revealed that Puag-Haad, oxyresveratrol, pine bark and Trolox© at 100 μg/mL, appeared to produce equally low LDH release under UV-A, whereas L-ascorbic acid gave the highest release followed by EGCG. Puag-Haad and oxyresveratrol also showed a good anti-collagenase activity, with the respective mean IC₅₀ of 58.8 and 153.1 μg/mL, which were less potent than EGCG (8.0 μg/mL) and pine bark (21.9 μg/mL) but much more potent than L-ascorbic acid (1.331 mg/mL) and Trolox© (2.348 mg/mL). Moreover, both Puag-Haad and oxyresveratrol could reduce the extent of DNA damages caused by UV-A as detected by flow cytometry. In conclusion, the multi-functional beneficial effects of A. lakoocha extracts may have a strong potential uses in cosmetics and other health-related products.