Microwave-Assisted Extraction of Ricinine from Ricinus communis Leaves.

Liliane Nebo,Rosa M Varela,João B Fernandes,Miguel Palma

doi:10.3390/antiox8100438

Abstract

The alkaloid ricinine (3-cyano-4-methoxy-N-methyl-2-pyridone) is found in different parts of the Ricinus communis plant and is known to possess several bioactive properties, including strong antioxidant activity. In this study, a new microwave-assisted extraction (MAE) method was developed for the recovery of ricinine from R. communis leaves. The extraction variables studied were extraction temperature (between 125 °C and 175 °C), microwave power (between 500 W and 1000 W), extraction time (between 5 min and 15 min), extraction solvent (between 10% and 90% of EtOAc in MeOH), and solvent-to-sample ratio (between 25:1 mL and 50:1 mL of solvent per gram of the sample). On studying the effects of extraction variables, both solvent and liquid-to-solid ratio were found to exhibit the highest effects on ricinine recovery. A fast (15 min) microwave-assisted extraction method was developed (high temperatures can be applied because the stability of ricinine is proven in the literature), allowing for the recovery of ricinine from R. communis leaves. The study revealed that R. communis leaves had almost 1.5 mg g−1 (dried weight) of ricinine.

Highlights

Ricinus communis J. (Euphorbiaceae) is a plant found in most regions of Brazil and other tropical areas [1]
Castor bean (R. communis) is widely used for the production of castor oil, which is used in cosmetic industries, and in the manufacturing of bio fuel
Ricinine is considered a promising cognition-enhancing drug for the treatment of patients with amnesia [3]. It is responsible for the R. communis insecticide activity [4], against leaf-cutting ants (Atta sexdens rubropilosa) [5] and other insects [6]

Summary

Introduction

Ricinus communis J. (Euphorbiaceae) is a plant found in most regions of Brazil and other tropical areas [1]. The alkaloid ricinine (3-cyano-4-methoxy-N-methyl-2-pyridone) is found in the oil, leaves, and flowers of R. communis, and is known to offer anticonvulsant activity [2]. Ricinine is considered a promising cognition-enhancing drug for the treatment of patients with amnesia [3]. It is responsible for the R. communis insecticide activity [4], against leaf-cutting ants (Atta sexdens rubropilosa) [5] and other insects [6]. Leaf-cutting ants are one of the main herbivores in the Neotropics and are considered an huge pest to agricultural crops and forests with exotic trees, such as Eucalyptus ssp in Brazil. Strong antioxidant results were recently found for extracts from R. communis leaves, due to the high levels of ricinine [7,8]

Methods

Results

Conclusion