Extraction of bioactive compounds and free radical scavenging activity of purple basil (Ocimum basilicum L.) leaf extracts as affected by temperature and time.

Alessandra C Pedro,Fernanda Moreira,Neiva D Rosso,Daniel Granato

doi:10.1590/0001-3765201620150197

Alessandra C Pedro, Fernanda Moreira + Show 2 more

Open Access

https://doi.org/10.1590/0001-3765201620150197

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Abstract

In the current study, response surface methodology (RSM) was used to assess the effects of extraction time and temperature on the content of bioactive compounds and antioxidant activity of purple basil leaf (Ocimum basilicum L.) extracts. The stability of anthocyanins in relation to temperature, light and copigmentation was also studied. The highest anthocyanin content was 67.40 mg/100 g extracted at 30 °C and 60 min. The degradation of anthocyanins with varying temperatures and in the presence of light followed a first-order kinetics and the activation energy was 44.95 kJ/mol. All the extracts exposed to light showed similar half-lives. The extracts protected from light, in the presence of copigments, showed an increase in half-life from 152.67 h for the control to 856.49 and 923.17 h for extract in the presence of gallic acid and phytic acid, respectively. These results clearly indicate that purple basil is a potential source of stable bioactive compounds.

Highlights

Purple basil (Ocimum basilicum L.) is one of the species that belongs to a group of medicinal and aromatic plants of economic value worldwide, especially in Brazil where it is vastly used in traditional dishes, in the folk medicine, and various pharmaceutical applications (Rosas et al 2004, Lee et al 2005)
Still there is a clear lack of studies regarding the evaluation of the effects of the main factors that influence the extraction of bioactive compounds from purple basil, and the evaluation of the stability of anthocyanins toward temperature, light and copigmentation. Based on this fact and taking into account the importance of new sources of natural colorants that can be applied in pharmaceutical, medical and food products, the objective of this study were to evaluate the effect of time and temperature on the extraction of bioactive compounds and antioxidant activity of purple basil leaves using response surface methodology, and to evaluate the stability of anthocyanins toward temperature, light and copigmentation
The Ocimum basilicum L. leaf extracts presented a high content of total phenolics (272 – 688 mg/100 g) in which about 14.49 to 16.12% are made of total flavonoids (40.49 – 106.23 mg/100 g)

Summary

Introduction

Purple basil (Ocimum basilicum L.) is one of the species that belongs to a group of medicinal and aromatic plants of economic value worldwide, especially in Brazil where it is vastly used in traditional dishes, in the folk medicine, and various pharmaceutical applications (Rosas et al 2004, Lee et al 2005). The purple basil and belongs to the Lamiaceae family and its chemical composition is composed of an appreciable amount of phenolic compounds, especially flavonoids (Capecka et al 2005, Carvalho-Filho et al 2006). Nguyen et al (2010) studied leaves of three cultivars of purple basil, namely Dark Opal, Sweet Thai, and Genovese, and observed that the basil treated with a higher potassium rate (5.0 mM) resulted in an increase in the concentration of total phenolic compounds and antioxidant activity as compared to the basil treated with a lower potassium rate (1.0 mM).

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