Chemical composition and antioxidant activity of Indigofera suffruticosa

Abstract

Indigofera suffruticosa Mill. (Fabaceae), popularly known as "anil," is an endemic shrub, which is distributed in tropical America [1]. This plant species is used as a source of indigo dye, and its leaves and roots are popularly used against urinary tract disease, disorders of the nervous system, joint pain and neuralgic, epilepsy, spasm, fever, nose bleeding, acute inflammation of the skin, hepatitis, scabies, and gonococcal urethritis [2]. The literature points to studies on its several biological activities [3][4][5][6][7][8], and chemical investigations have been made previously [9-11] on this species; nevertheless, to the best of our knowledge, only one report has appeared concerning the volatile chemistry of this genus [12].Restrictions on the use of synthetic antioxidants are being imposed because of their potential carcinogenicity [13]. Therefore, the purpose of this study was to assess the antioxidant activity (Table 1) and the chemical composition of its pods. The presence of gallic acid, which is known to be a powerful antioxidant [14], seems to be responsible for its radical scavenging activity (1.55·10 -2 r 3.0·10 -4 mg/mL), as shown by the ethanol extract of pods of I. suffruticosa.Successive chromatographic treatments of the ethanol extract of the air-dried pods of I. suffruticosa afforded sitosterol and gallic acid. The structures of these compounds were established based on the comparison of 1 H and 13 C NMR data with the literature [15,16].The essential oil from the leaves of I. suffruticosa was analyzed by CG/MS to determine their constituents. Thirteen constituents were identified in the oil of I. suffruticosa leaves representing 96.8% of the total oil fraction, and the major constituents were phytol (75.8%) and methyl linoleate (9.1%) ( Table 2).The results indicated that I. suffruticosa essential oil was characterized mainly by a large amount of a linear diterpene (78.5%), the esters of fatty acids (12.8%) and aliphatic compounds (8.2%), and by the lack of mono-and sesquiterpenes.To the best of our knowledge, the only study on the essential oil of Indigofera genus in the literature is on I. microcarpa [12] and shows no similarities between the oils. The oil of I. microcarpa has the sesquiterpenes E-caryophyllene and D-humulene as the main constituents but no diterpenes and fatty acids. This fact suggests the chemical variability among the oils of the genus Indigofera.

Composition and antioxidant potential of leaf and stem essential oils from Nigerian Indigofera spicata Forssk

“…This result is consistent with report on the essential oil procured from Indigofera microcarpa, which has caryophyllene and-humulene-sesquiterpenes which has major constituents (Arriaga et al, 2008). Presence of esters of fatty acids were also reported in the oil of Indigofera suffruticosa (Arriaga et al, 2013). However, unlike the oils from I. suffruticosa which has the linear diterpenes (78.5%) as the most abundant class of compounds (Arriaga et al, 2013), diterpenoids found in the oil of I. spicata leaf was only 3% of the essential oil composition.…”

“…Presence of esters of fatty acids were also reported in the oil of Indigofera suffruticosa (Arriaga et al, 2013). However, unlike the oils from I. suffruticosa which has the linear diterpenes (78.5%) as the most abundant class of compounds (Arriaga et al, 2013), diterpenoids found in the oil of I. spicata leaf was only 3% of the essential oil composition. This shows the chemical variations in the oils of the different species of the genus Indigofera.…”

Indigofera suffruticosa Mill. (Anil): Plant Profile, Phytochemistry, and Pharmacology Review

“…The presence of such compounds in the leaf oil of I. suffruticosa , ( z )-3-hexenyl benzoate, methyl hexadecanoate, phytol, linoleic acid, methyl linoleate, n -docosane, n -tricosane, was also found [30].…”

“…Ethanolic extracts of leaves of I. suffruticosa stand out with potent antioxidant activity in an experimental model in vitro with the free radical 2,2-diphenyl-1-picrilidrazil (DPPH), and this method is a rapid way to measure the antioxidant capacity of compounds, it is based on the reduction of DPPH in solution, and this action is attributed to the presence of high concentrations of gallic acid in the extract [30]. Plants contain several phytochemicals, such as phenolic compounds, which have promising antioxidant activity, mainly in the prevention of chronic diseases.…”

Effects of <i>Indigofera suffruticosa</i> Miller (Wild indigo) leaves aqueous extract subacute supplementation in mice

“…I. suffruticosa is used in popular medicine as antispasmodic, antiepileptic, purgative, antipyretic, sedative (Hastings, 1990), in colic and kidney diseases (Matos, 1999), as a stomach enhancer and diuretic (Agra et al, 2007). Studies proved that it has anti-inflammatory activity (Leite et al, 2003;Nascimento et al, 2022), antioxidant (Arriaga et al, 2013), chemopreventive (C.C. Chen et al, 2013), and gastroprotective (Luiz-Ferreira et al, 2011).…”