Surfactants produced from three plant extracts –quinoa, soyabean and acerola cherry – could offer an alternative to synthetic shampoo ingredients, according to a new study reported by Cosmetics Design.

Conducted by a research team in Brazil, the results of the “Application of Plant Surfactants as Cleaning Agents in Shampoo Formulations”​ were published in Processes, the 12 October report said.

“The development of cosmetic formulations using plant-derived biosurfactants is promising and constitutes an alternative to cosmetics formulated exclusively with synthetic surfactants,” the authors wrote.

The three surfactant rich extracts were from Chenopodium quinoa (quinoa)​, Glycine max (soyabean)​, and Malpighia emarginata​ (acerola cherry). Seeds from quinoa and soyabean were made into a powder, then an extract. Fruit from acerola cherry was made into a flour, then an extract.

As part of the study, the properties of the three extracts were analysed – alone and within formulations, to evaluate their potential to replace or decrease the amount of synthetic surfactants in shampoos.

Each extract was analysed for stability, antioxidant capacity, irritation, cleaning potential and toxic potential, the report said.

The three extracts were used in seven shampoo formulations to measure surface and interfacial tension reduction.

For comparison, all seven shampoo formulations were tested for a range of factors, including pH, dirt dispersion and cleaning ability – alongside a commercially available moisturising shampoo.

All formulations remained stable within temperature and pH ranges. Soyabean and quinoa recorded low and no toxicity, respectively, while pH ranges were within normal ranges during stability tests for those typically used in cosmetic formulations.

The highest antioxidant activity was recorded in the acerola cherry formulation, which could make it suitable for use as a multifunctional additive, Cosmetics Design wrote.

All extracts were classified as less irritating than sodium lauryl sulphate, a surfactant commonly used in shampoos.

The formulations all recorded a similar sebum removal capacity as commercial shampoo, particularly formulations combined with 10% disodium cocoyl glutamate (DCG).

For the shampoo formulations, the F1 version contained no surfactant, F2 contained 4% DCG and the other formulations contained 10% primary surfactant combined with 4% DCG as a secondary surfactant.

All shampoos tested had acceptable surface tension, density, foam formation and dirt dispersion, Cosmetics Design wrote.

Three shampoo formulations — DCG and acerola cherry, DCG and soyabean, and DCG and quinoa and soyabean – recorded the highest cleaning potential.

Shampoo containing only DCG as the surfactant had a lower sebum yield compared to the other combinations, meaning the plant extracts helped improve cleaning potential.

“The … study showed that formulating shampoos with a lower concentration of synthetic surfactants than the current practice would be possible and that plant-derived surfactants have properties suitable for obtaining good alternative natural products,” the authors wrote.

“Among the formulations produced, five of them … have the potential to undergo subsequent quality-control tests and become commercial formulations.”