In today’s world, increasing pollution and disturbed ecosystems are creating conditions that make humans more likely to get infectious diseases. Factors, such as rising global temperatures and humidity, facilitate the growth of harmful microorganisms and disrupt the balance between hosts and microbes, leading to more infections. The overuse of antibiotics, improper disposal of biomedical waste, poor infection control, and a lack of new antimicrobials have contributed to a global rise in antimicrobial resistance (AMR). There is an urgent need for innovative antimicrobial strategies that use more natural and gentle antimicrobial agents instead of conventional synthetic antibiotics. Plant-derived saponins are considered a potential solution because they are natural surfactants and emulsifiers with antimicrobial activities. Vitamin E, also known as tocopherol, is a fat-soluble antioxidant known to protect cells against damage, and its anti-inflammatory properties may promote healing. Therefore, a saponin–vitamin-E (SE) emulsion is being explored as a natural, gentle, and antioxidant-rich alternative for targeted antifungal treatments.
Methods
Saponin was extracted from Acacia concinna. An oil-in-water emulsion was prepared using vitamin E as the oil phase and an aqueous saponin solution as the aqueous phase. The emulsion was prepared using sonication, centrifugation, and magnetic stirring. The emulsion was characterized using spectrochemical methods, optical microscopy, and z-potential measurements. The antimicrobial activity of the emulsion was tested against bacterial and fungal strains using the agar diffusion method.
Key Points by Section
•Characterization and Stability Testing of Saponin–Vitamin-E Emulsion:
◦The particle size of the emulsions decreased with increasing saponin concentration up to 0.5% (w/w), after which it remained constant.
◦FTIR spectral analysis confirmed a strong interaction between saponin and vitamin-E, indicating the formation of a stable emulsion.
◦The emulsion with a saponin concentration of 0.5% (w/w) exhibited the best thermal stability over a varied temperature range.
◦The high negative z-potential value at pH 9 (-41 mV) enhances electrostatic repulsion between droplets, preventing aggregation and stabilizing the emulsion.
◦Shelf-life studies showed that the emulsion was stable for up to 45 days under both refrigerated and ambient conditions, with the refrigerated emulsion showing almost no change in droplet size over 90 days.
•Determination of Emulsifying Properties:
◦Emulsification capacities (CE24 and CE720) and emulsion stability (SE) were calculated to assess the emulsion’s ability to maintain its structure over time.
◦The emulsion showed good emulsification capacity and stability, indicating its potential for use in various applications.
•Study of Antimicrobial Activity:
◦The saponin sample showed inhibitory activity against Pseudomonas aeruginosa and significant antifungal activity against Aspergillus flavus and Candida albicans.
◦The saponin emulsion exhibited potent antifungal properties against Aspergillus flavus and Candida albicans, but did not inhibit the growth of the tested bacterial strains.
◦The selective inhibitory effect of the saponin emulsion on specific fungal strains suggests its potential application in targeted antifungal treatments.
•Prospects:
◦The formulation of an antifungal cream utilizing an SE emulsion presents a promising approach to combating microbial infection and promoting skin health.
◦Further research is required to explore potential saponin-based creams by choosing appropriate thickening agents for the cream base, the optimal saponin concentration along with vitamin E or other components for skin moisturization and product performance, and suitable preservatives for product conservation over a prolonged period.
◦Incorporating the o/w emulsion into a nanotechnology-based targeted drug delivery system could enhance its efficacy in antifungal activity.
This research highlights the potential of using Shikakai (Acacia concinna) saponin as a sustainable and practical source for natural surfactants. The saponin–vitamin-E emulsion demonstrates exceptional stability, desirable emulsion characteristics, and significant antifungal activity against Aspergillus flavus and Candida albicans. The emulsion’s stability, unique structure, and the antioxidant properties of vitamin E make it an excellent candidate for treating fungus-affected skin and scalp issues. This innovative formulation is poised to make a substantial impact in natural remedies for pharmaceutical and cosmetic industries, offering a promising alternative to synthetic antifungals. Future research could explore its incorporation into nanotechnology-based drug delivery systems and the development of topical creams, ointments, and shampoos for treating fungal infections.
Link to the study: https://pubs.rsc.org/en/content/articlehtml/2025/ra/d4ra08297d
