Quantitative determination of pigments in moringa leaves

Abstract

Background. Moringa oleifera leaves are promising medicinal raw materials. Leaves contain a complex of biologically active compounds: proteins, minerals, carotenoids, vitamins (thiamine, riboflavin, ascorbic acid), glycosides, flavonoids (rutin, quercitin) [1, 2]. The main complexes of natural pigments in moringa leaves are chlorophyll derivatives and carotenoids represented by chlorophyll a and β-carotene [3, 4]. Carotenoids have antioxidant, radioprotective and anti-carcinogenic activity [5–8]. Chlorophylls have anti-inflammatory, wound-healing and antibacterial effects, and also have an antioxidant effect [5, 9]. Currently, it is important to study biologically active compounds (BAC), in particular pigments that have antibacterial and anti-inflammatory properties. Currently, methods for the quantitative determination of carotenoids and chlorophyll have not been developed on the moringa’s raw materials, and a variant of the quantitative determination method is provided in this paper. The results of the study can be used to develop regulatory documentation for promising medicinal plant raw materials. The purpose of the study is to develop methods for quantitative determination of carotenoids and chlorophyll content in Moringa leaves. Materials and methods. The objects of research were dried Moringa leaves harvested in the Penza region. Qualitative analysis of pigments was performed by TLC from the acetone fraction using a system of solvents: petroleum ether-acetone (6:4) [5, 9]. For the quantitative determination of carotenoids and chlorophylls in extracts from raw materials of Moringa used spectrophotometric method [10–13]. Quantitative determination of carotenoids and chlorophylls in Moringa raw materials was performed using 95 % ethyl alcohol, hexane, acetone, and a mixture of acetone-hexane (1:2). Optical density was measured at the maximum absorption of carotenoids (450 nm) and chlorophyll a (664 nm). Results. 3 spots are visually determined, one of which is yellow with Rf = 0,91 refers to β-carotene, and blue-green and yellow-green spots with Rf = 0,9 and 0,08 refer to chlorophylls a and b, respectively. Conclusions. The concept of a method for determining carotenoids and chlorophyll is presented. It was found that the best extractant for carotenoid extraction (66,31 mg%) is a mixture of acetone-hexane (1:2), chlorophyll (0,23 %) a mixture of acetone-hexane (1:2).

Keywords

• moringa oleifera
• β-carotene
• chlorophyll a
• spectrophotometry
• thin-layer chromatography