A New Oleanane Type Saponin from the Aerial Parts of Nigella sativa with Anti-Oxidant and Anti-Diabetic Potential

Abstract

Natural product studies explore potential and interesting new compounds to discover innovative drugs. Nigella sativa (N. sativa) (Ranunculaceae) is traditionally used to treat diabetes. Flavonoids and triterpenoid mostly show anti-diabetic activity. The current study aim to identify new compounds by a systematic study of the anti-oxidant and anti-diabetic activity of aerial parts of N. sativa concerning. Phytochemicals were isolated from the methanolic extract of aerial parts of the plant by column chromatography and identified by nuclear magnetic resonance spectroscopy and mass spectroscopy. A new triterpenoid saponin glycoside was isolated along with flavonoids. The anti-diabetic study was carried out by DPPH, ABTS, α -glucosidase, and protein tyrosine phosphatase 1B assays at doses of 12.5 to 250 µM. The isolated phytochemicals were identified as 3-O-(β-d-xylopyranosyl-(1-3)-α-l-rhamnopyrnaosyl-(1-2)-α-l-arabinopyranosyl]-28-O-(α-l-rhamno-pyranosyl-(1-4)-β-d-glucopyranosyl-(1-6)-β-d-glucopyranosyl] hederagenin (1), flaccidoside III (2), catechol (3), quercetin-3-gentiobiosides (4), magnoflorine (5), nigelflavonoside B (6), nigelloside (7), quercetin sphorotrioside (8), kaempferol-3, 7-diglucoside (9), kaempferol 3-O-rutinoside (10), rutin (11), 3-O-[α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranpsylhederagenin (12), 3β,23,28-trihydroxyolean-12-ene-3-O-α-l-arabinopyranoside(1→4)-a-rhamnopyranosyl,(1→4)-β-d-gluco-pyranoside (13), 3-O-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranpsyl]-28-O-β-d-gluco-pyranosyl hederagenin (14), and α-hederin (15). These were isolated and are reported for the first time in this study. Compared 13 was identified as a new compound. Compound 2 was isolated for first time from the genus Nigella. Compound 6 was found to be the most active in the DPPH, and ABTS assays and compound 10 was found to be the most active in the α-glucosidase assay, with IC50 32.7 ± 0.1, 95.18 ± 0.9, 214.5 ± 0.0 µΜ, respectively. Compound 12, at a dose of 125 µΜ, showed anti-diabetic activity in a PTP1B assay with IC50 91.30 ± 2.5 µΜ. In conclusion, the anti-diabetic activity of N. sativa is due to its flavonoids and TTSGs. Therefore, our studies suggest that the aerial parts of N. sativa are also a valuable and alternate source of valuable phytochemicals that could be used to develop anti-oxidant and anti-diabetic medicines.

Nitric Oxide as a Target for Phytochemicals in Anti-Neuroinflammatory Prevention Therapy

“…Natural products and their derivatives are rich sources of active and novel compounds that may be used against several adverse conditions including cancers, diabetes, inflammatory diseases, metabolic diseases, neurological diseases, and many others [ 118 , 119 , 120 , 121 , 122 , 123 , 124 ]. NO, a unique biological neurotransmitter, is involved in the initiation of several biological and pathological conditions, including immunomodulation, inflammation, and neuronal transmission in the central and peripheral nervous systems, which may lead to neurological disorders.…”

Metabolomics and Molecular Networking to Characterize the Chemical Space of Four Momordica Plant Species

“…The chemical complexity of saponins is described as the gap between understanding the relationship between their structures and the relative pharmaceutical and medicinal properties [39]. Various activities have been attributed to these glycosides, such as anti-diabetic, anti-inflammatory [40][41][42], anti-tumour and anti-bacterial activities [43]. In this study, 19 saponins were identified, including cycloartane triterpenoids.…”

Nigella sativa L. Phytochemistry and Pharmacological Activities: A Review (2019–2021)

“…Inhibition of peroxidase activity is another benefit of flavonoids, which allows the prevention from oxygen reactive species [ 18 ]. Among the extracted phenolic compounds from the NS seeds ( Figure 2 ), we mention gallic acid, ferulic acid, vanillic acid, p-coumaric acid, chlorogenic acid, catechin, quercetin, apigenin, rutin, nigelflavonoside B, and flavone [ 19 , 20 ].…”

“…Between the years 1985 and 1995 different NS alkaloids were isolated and identified ( Figure 3 ) such as nigellicine which is composed of an indazole nucleus [ 21 ], nigellimine which is an isoquinoline molecule [ 22 ], also nigellimine N-oxide, and finally nigellidine which is a molecule of indazole nature [ 23 ]. While another molecule called magnoflorine was recently identified in the aerial part of the NS plant [ 20 ].…”