Effect of combinations of emblica officinalis extract, achras sapota extract and silymarin on in vitro anti-aging activities

Abstract

Since skin aging is an unavoidable condition involving several pathways, a combination of extracts in skincare product to alleviate the skin aging and improve skin condition becomes common. However, there are a few reports that showed the influence of combined extracts on their biological activities. This study aims to investigate an effect of combined extracts on their antioxidant, anti-collagenase and anti-elastase activity when compares with each individual extracts. Ethanolic amla (Emblica officinalis) extract, ethanolic sapota (Achras sapota) extract and silymarin were individually screened for antioxidant, anti-collagenase and anti-elastase properties as well as were quantified for their total phenolic content and total flavonoid content. The antioxidant capacity was evaluated by colorimetric methods. The effects of MMP-1, MMP-2 and elastase inhibitions were determined by using the gelatinase/collagenase and elastase assay kits (EnzChek®). The quantities of phenolic and flavonoid compounds were determined by Folin-Ciocalteu and aluminium chloride colorimetric methods, respectively. Two extracts were chosen from their superior activities on for anti-oxidant, anti-collagenase and anti-elastase and were used in the combination study. The effect of combination was reported as combination index (CI) and categorized into three types: synergism (CI < 1), additive (CI = 1) or antagonism effects (CI > 1), respectively. The reference combination index was calculated at the median effect. Regarding to antioxidant activity, ethanolic amla extract showed the most potent activity with IC50 values of 1.61 ± 0.04 μg/mL. While ethanolic sapota showed the highest inhibitions on collagenase and elastase with IC50 of 86.47 ± 3.04 μg/mL and 35.73 ± 0.61 μg/mL, respectively. Therefore, amla and sapota were combined at different combination ratios. The combination index at median effect was revealed additive effect (CI = 1.00 ± 0.02) on anti-oxidant activity. But the amla and sapota combinations exhibited synergist effects on inhibitions of MMP-1 (CI = 0.79 ± 0.02) and MMP-2 (CI = 0.58 ± 0.02) and elastase (CI = 0.76 ± 0.04). Surprisingly, the elastase inhibitions of the combination at concentration other than the median point, antagonist effect could be observed at particular combination ratios. For the elastase inhibition, the effects could be synergist or antagonist depending on the combination ratios. In conclusion, combining extracts or actives could have an influence on the biological activities. Some activities showed additive effect presenting no advantage over usage of single extract while some showed synergist effect demonstrating some advantages. The importance of combination ratios was seen for anti-elastase activity but not for others; therefore, some special tests may be required at earlier stage of product development.