LC-MS Characterization and Biological Activities of Cuban Cultivars of Plectranthus neochilus Schltr.

Annarli O Rodríguez-Ferreiro,Kenn Foubert,Wim Vanden Berghe,Frenkel Guisado-Bourzac,Ania Ochoa-Pacheco,Lianet Monzote,William N Setzer,Paul Cos,Silvia Molina-Bertrán,Emilia Ortiz-Beatón,Oneida Font-Salmo,Claudina Perez-Novo,Julio C Escalona-Arranz,Luc Pieters,Daniel Méndez-Rodriguez

doi:10.3390/plants11010134

Abstract

Plectranthus neochilus Schltr. (Lamiaceae) is a plant recently introduced in Cuba. Worldwide, it is an ethnomedicinal alternative for its use against microbial infections, but the Cuban population use the extracts to treat sleep disorders. To address this apparent incongruity, four collections (from different seasonal conditions in the year) of Cuban P. neochilus cultivars were analyzed in terms of their pharmacognostic characteristics. Three extracts using fresh and dried leaves were chemically and biologically characterized. UPLC-DAD-MS/MS analysis was performed to determine their chemical composition, while a panel of nine microorganisms was used to evaluate their antimicrobial activity. Finally, cytotoxic effects of different fractions were measured in three cell lines by the resazurin viability assay. In contrast to previously reported micro and macromorphological properties of P. neochilus, the leaves from the Cuban cultivars did not present glandular trichomes, nor did they produce quantifiable levels of essential oils. Moreover, aqueous extracts used by the population revealed no significant antimicrobial activity and were not cytotoxic. The three extracts showed a similar phytochemical composition, i.e., eight flavonoids, seven abietane diterpenes, and rosmarinic acid as the major constituent, most of them reported for the first time in this species. The low yield of essential oil, the absence of glandular trichomes, compounds with a high level of oxidation, and a moderate antimicrobial activity detected were the most distinctive pharmacognostic and biological characteristics of P. neochilus grown in Cuba. These aspects could explain its non-use as an antimicrobial.

Highlights

The World Health Organization (WHO) highlights that about 80% of the population from developing countries make use of medicinal plant remedies as a cost-effective way to solve health problems
Their absence in the samples studied in the present work could be the explanation for such low production of essential oils, which probably remain stored in the internal vesicles maintaining the characteristic smell of the plant
The pharmacognostic, phytochemical, and biologic profiles of Cuban cultivars of P. neochilus were analyzed for the first time

Summary

Introduction

The World Health Organization (WHO) highlights that about 80% of the population from developing countries make use of medicinal plant remedies as a cost-effective way to solve health problems. Low-income countries have limited access to expensive commercial drugs on the international market, which forces people to resolve health issues with natural herbal plants/remedies [1]. In this context, natural products or natural product derivatives continue to lead the process of obtaining new entities in drug discovery. Natural medicines should be the focus of underdeveloped countries as a way to solve their own health problems and to get access to new income sources

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