Evaluation of In Vitro Antioxidant Activities and Toxicity Effects of a Novel Plant-Based Body Lotion from Thai Medicinal Plants

Abstract

In Thailand, several polyherbal formulations have been used for treating various diseases, including skin infections. 10 In the present work, a polyherbal formulation for treating skin diseases, known as THR-01, consisting of Rhinacanthus nasutus (Acanthaceae), Quisqualis indica (Combretaceae), Ocimum sanctum (Lamiaceae), Vitex glabrata (Verbenaceae), and Stemona tuberosa (Stemonaceae) was chosen for testing its antioxidant activities and safety. Interestingly, Stemona tuberosa, one of the primary components of this formulation was found to exhibit significant antioxidant properties with low toxicity. Plant roots of the Stemona genus, part of the Stemonaceae family, have historically been a part of traditional Chinese medicine, valued for their capabilities in repelling insects and relieving coughs. The root extracts of these plants can be applied for external use in repelling various insect pests. [11][12][13] Additionally, Stemona root extracts exhibit promising antibacterial properties against some skin infecting pathogens. According to previous research, ethanol extracts of Stemona tuberosa roots have been shown to suppress a broad spectrum of bacteria and fungi. 11 More recent studies have isolated eight new alkaloids from the roots of Stemona tuberosa and one of these compounds showed good anti-inflammatory activity. 14 Therefore, to develop an effective herbal product for external use, especially for the skin, an extract of Stemona tuberosa, the active component of a traditional formula used for treating skin diseases in Southern Thailand, was tested for its antioxidant activity using 1,1diphenyl-2-picrylhydrazyl (DPPH), total phenolic content (TPC), and ferric-reducing antioxidant power (FRAP) assays. Its toxicity profile using an in vivo model, Galleria mellonella larvae, was determined, ensuring the safety of the extract for potential cosmetic use, according to the aim of this research. Moreover, consumer acceptance of the resulting body lotion containing various concentrations of Stemona tuberosa extracts was assessed, focusing on sensory attributes such as