Phytochemical study and bioactivity assessment of extracts from Plectranthus ecklonii Benth

Plectranthus genus plants belong to Lamiaceae family, commonly known for their use as aromatic and medicinal properties. Furthermore, Plectranthus species are particularly rich in phenolic compounds and abietane-type diterpenes, such as royleanones, able to justify their use in traditional medicine against a wide range of diseases, including skin disorders and cancer [1], [2].

In order to study the phytochemical composition and the biological activity of P. ecklonii Benth., ultrasound-assisted extractions were carried out using methanol and acetone as extraction solvents.

The phytochemical analysis revealed the predominant presence of phenolic compounds in the methanolic extracts, while abietanes were identified as the most occurring secondary metabolites in the acetone ones.

Methanolic extracts were screened to assay their potential bioactivity as antioxidant, antimicrobial and on skin-related enzymes, as well as their general toxicity. The results showed a very promising antioxidant activity, but only a moderate effect against bacteria; however, no relevant general toxicity was highlighted. Good tyrosinase inhibition was observed, together with an excellent inhibitory activity on collagenase, making the methanolic extract a promising raw material to be used for the development of dermocosmetic formulations, especially those with anti-ageing activity.

Considering safety issues, only diterpene Parviflorone D ([Fig. 1]) has been isolated and characterized from acetone extracts. Its cytotoxic activity has been evaluated against several cancer cell lines, always showing an IC₅₀ in the low micromolar range.

Fig. 1 

Further studies are currently ongoing on both the extracts to investigate about other relevant biological activities and ascertain their safety, for internal and topical uses.

• References

• 1 Antão AR, Bangay G, Domínguez-Martín EM. et al. Plectranthus ecklonii Benth: A Comprehensive Review Into its Phytochemistry and Exerted Biological Activities. Front Pharmacol 2021; 12: 768268
• 2 Marçalo J, Domínguez-Martín EM, Nicolai M. et al. Screening the Dermatological Potential of Plectranthus Species Components: Antioxidant and Inhibitory Capacities over Elastase, Collagenase and Tyrosinase. J Enzyme Inhib Med Chem 2021; 36 (01) 257-269

Publication History

Article published online:
12 December 2022