Exploring synergistic potential of Turmeric (Curcuma longa L.) and Green tea (Camellia sinsensis [L.] Kuntze) against skin extracellular matrix enzymes, antioxidant and anti-inflammatory activity

Background: Turmeric ( Curcuma longa L.) and Green tea ( Camellia sinensis [L.] Kuntze) have a long history of traditional use in Ayurveda due to their potent antioxidant action in managing several skin conditions. Aims and Objectives: To evaluate the synergistic effects of Turmeric Extract (TE) and Green Tea Extract (GTE) on key enzymes related to skin aging, pigmentation, and inflammation. The primary objective was to investigate and assess the synergistic effect of both extracts on target enzymes, thereby achieving significant efficacy with a minimal concentration of individual drugs, thereby reducing the risk of side effects and providing a basis for the development of an effective skin-care formulation. Materials and Methods: Inhibition against collagenase, elastase, hyaluronidase, and tyrosinase was tested using enzyme inhibition assays, and the anti-inflammatory potential was tested through cyclooxygenase-2 (COX-2) and lipoxygenase (LOX) inhibition. The study also evaluated the antioxidant activity through 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), Ferric Reducing Antioxidant Power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl assays. A synergistic action of both extracts was established using CompuSyn software against each target enzyme. The in vitro cytotoxicity of the extracts on the 3T3 and L929 fibroblast cells was determined to establish the safety profile of the extracts. Results: Both TE and GTE presented significant inhibitory activities against all tested enzymes in a dose-dependent manner. A 1:1 (w/w) mixed preparation of TE and GTE showed synergistic activities compared to each single compound, as shown by a Combination Index of < 1 computed using CompuSyn. The best inhibition of collagenase was obtained with the combination (IC 50 = 7.94 μg/ml) and elastase (IC 50 = 4.29 μg/ml), including enzymes crucial for skin elasticity. Tyrosinase inhibition (IC 50 = 26.05 μg/ml) holds some promising prospects regarding pigment control. Finally, the considerable COX-2 and LOX inhibition (IC 50 = 1.98 μg/ml and 14.02 μg/ml, respectively) evidently confirms good anti-inflammatory ability in these extracts. The cytotoxicity tests had confirmed that the extracts are nontoxic over the entire tested concentration range. Conclusion: Results showcase the combination of TE and GTE as promising agents in the direction of antiaging, antipigmentation, and anti-inflammatory skincare applications. The synergistic activity between extracts could allow them to be used at lower doses without losing their efficacy; in this respect, they seem to be an interesting alternative for natural skincare formulations.