Abstract:
Grammatophyllum speciosum Blume (Orchidaceae) is a large-sized orchid in Southeast Asia. The aim of this study was to evaluate G. speciosum pseudobulb extract for anti-aging activities, both in vitro and in vivo. In vitro anti-aging activity was performed using non-cell and cell-based assays. In vitro study, G. speciosum pseudobulb extract exhibited a high content of gastrodin, which was used as an active analytical marker. The total content of the antioxidant polyphenols in G. speciosum ethanolic extract was 48.19 ± 0.39 mg epigallocatechin gallate (EGCG) equivalent / g extract. The anti-collagenase enzyme activity of the ethanolic extract of the pseudobulb of G. speciosum was lower than EGCG (IC50 1179.47 and 0.056 µg/mL, respectively ). The clinical test for skin irritation using prophetic patch test method was conducted in healthy Thai volunteers. The randomized double-blind, placebo-controlled trial was further conducted for efficacy assessment during 56 days of serum application, as observed by Visioface© and Cutometer©. However, the G. speciosum extract possessed higher anti-elastase activity than that of EGCG (IC50 71.10 and 92.52 µg/mL, respectively), that was to confirm the activity of anti-wrinkle on the skin. Moreover, G. speciosum extract showed a potential to enhance stem cell behaviors and markers of human keratinocyte cells (HaCaTs). This ethanolic extract was also able to protect cells against superoxide anion-induced cell death at concentration of 20 µg/mL in HaCaTs. The G. speciosum pseudobulb extract was subsequently formulated into a viscous serum at 0.5% w/w for further safety and efficacy evaluation. The serum was found to be non-irritating and safely increase the skin distensibility (R0) level in healthy volunteers. The skin viscoelasticity (R6) and wrinkle volume were also significantly reduced, indicating the extract’s efficacy as a novel anti-aging agent. In summary, G. speciosum pseudobulb extract is beneficial for skin aging treatments, as indicated through both the in vitro tests and in vivo skin evaluation in human Thai volunteers. G. speciosum pseudobulb extract thus has a potential for development into a novel active standardized extract for anti-aging and/or treatment of age-related skin disorders.
