Herbal extract of Rhinacanthus nasutus, commonly known as snake jasmine, has been listed in Thailand National Medicinal Archive since the 2011 issue to the most current one of 2015 to be an ingredient of “Rhinacanthus Tincture” with property to heal fungal skin diseases such as ring worm and Athlete’s foot
However, the “Rhinacanthus Tincture” recipe does not indicate the type or amount of significant ingredient; the only key ingredient is shown as “Rhinacanthus nasutus leaves in ethyl alcohol 10% (w/v)”. The missing key ingredient here is rhinacanthin-C whose volume however can fluctuate during each extraction. This is because there are multiple variables – location, age, harvest time, and post-harvest method – that are effecting the quality and quantity of this ingredient in each batch. Evidently, there is a need to control these variables so to guarantee consistent amount and quality of rhinacanthin-C. In addition, tincture is not popular among users due to the irritation it may cause to soft tissues or open wounds. Therefore, the new recipe would also need to reduce amount of alcohol while add moisturizing agent to lessen irritation.
The development of Rhinacanthus tincture topical solution recipe uses green extraction –a method that saves time and energy including selecting environmentally-friendly solvent that needs not to be evaporated hence cutting cost and time. The green method controls the optimal amount and quality of rhinacanthin-C produced per batch via high performance liquid chromatography (HPLC) analysis. The extraction does not only increase popularity of the solution among users due to less irritation but also lift the standard of the extract at the international level.
The green extraction and topical solution recipe are described as to macerate Rhinacanthus leafs in glycerin in ethanol solvent 20% to 30% (v/v) which then passes through the process of microwave-assisted extraction resulting in > 2.0 mg/ml of rhinacanthin-C without chlorophyll. The final solution is ready to be used topically, without having to evaporate the solvent, composed of 0.1% (w/v) of rhinacanthin-C, to treat skin disease or inflammation caused by fungal or bacteria and especially causing reduced irritation. The recipe provides much increased stability to the solution than tincture.