Reassessment of the polar fraction of Stachys alopecuros (L.) Benth. subsp. divulsa (Ten.) Grande (Lamiaceae) from the Monti Sibillini National Park and its potential pharmacologic uses.

Abstract

Background:The phytochemical analysis of Stachys alopecuros subsp. divulsa, an endemic Italian species, has been recently reported and has showed the presence of 8-O-acetylharpagide (2), harpagide (3), allobetonicoside (4), and 4¢-O-galactopyranosyl-teuhircoside (5). In this paper, an in deep study of its glycosidic fraction with the aim to widen the knowledge on its secondary metabolites content is reported.Materials and Methods:Chromatographic techniques were used for the isolation of constituents while spectroscopic and spectrometric techniques were applied for the structures elucidation.Results:Besides the known constituents, all of them reconfirmed, ajugoside (1), reptoside (6) and 6-O-acetyl-ajugol (7) were also identified among the iridoids while the phenolic components resulted to be chlorogenic acid (8), b-arbutin (9), verbascoside (10), and stachysoside A (11), instead.Conclusion:The iridoid pattern of S. alopecuros subsp. divulsa has been expanded with the identification of not previously reported compounds as well as for the phenolic fraction. Except for the reconfirmed verbascoside (10), the other phenolic compounds were recognized for the first time in the studied species. The complete NMR assignment of compound (1) by means of bidimensional techniques is reported, and both the chemotaxonomic and pharmacological relevance of the isolated compounds is largely discussed.

Translational suppression of SARS-COV-2 ORF8 protein mRNA as a Viable therapeutic target against COVID-19: Computational studies on potential roles of isolated compounds from Clerodendrum volubile leaves

“…Compound 1 was characterized as harpagide, also known as (1 S ,4 aS ,5 R ,7 S ,7 aR )-7-methyl-1-[(2 S ,3 R ,4 S ,5 S ,6 R )-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-1,5,6,7 a -tetrahydrocyclopenta[c]pyran-4 a ,5,7-triol, having a molecular formula of C 15 H 24 O 10 . Harpagide, a close relative of ajugoside, has been reportedly isolated from Stachys alopecuros of the Lamiaceae family [ 37 , 38 ].…”

“…Elutes from 100% EtOAc showed 2 overlapping spots and were further separated using reversed-phase recycling HPLC with a solvent system of EtOAc:MeOH (80:20). Harpagide was obtained after several recycling cycles and was identified by comparison of its NMR spectral data with those reported in the literature [ [36] , [37] , [38] ].…”

Targeting the initiation and termination codons of SARS-CoV-2 spike protein as possible therapy against COVID-19: the role of novel harpagide 5-O-β-D-glucopyranoside from Clerodendrum volubile P Beauv. (Labiatae)

“…The 1 H NMR spectral of the isolated compound was compared to that of harpagide and allobentonicoside, compounds of close structural similarity as obtained in literatures (Jensen et al, 1989 ; Manguro et al, 2011 ; Venditti et al, 2017 ). While harpagide has only one glucose unit attached at C-1 to the iridoid aglycone unit, the allobentonicoside has two glucose units attached at C-1 and C-5 as in harpagide 5-O-β-D-glucopyranoside.…”

Iridoid glycosides and polyphenolic compounds from Teucrium chamaedrys L.

“…The initial eluting system was a solution of n-butanol and distilled water at concentration 82/18 (v/v) but, during the chromatographic run, this was changed raising its polarity in order to let the elution of the most polar compounds and so this passed to a solution of n-butanol, methanol and distilled water at concentration 70/10/30 (v/v/v). This first chromatographic separation led to the identification, by means of NMR and MS techniques and by comparison with data reported in literature, of six compounds: verbascoside (1) (Venditti et al, 2016a) as almost pure compound from the assembly of fraction 13-14 for the total weight of 62.0 mg; forsythoside b (2), samioside (3) and alyssonoside (4) (Saracoğlu et al, 2002;Yalçin et al, 2003) in mixture among them all in ratio 5:1:1 from the assembly of fractions 25-26 for the total weight of 46.2 mg; again forsythoside b (2) and samioside (3) (Saracoğlu et al, 2002;Yalçin et al, 2003) in mixture among them all in ratio 3:1 from the assembly of fractions 36-37 for the total weight of 22.4 mg; 8-O-acetyl-harpagide (6) (Venditti et al, 2016b(Venditti et al, , 2017a in mixture with forsythoside b (2) (Saracoğlu et al, 2002) in ratio 3:1 from the assembly of fractions 82-86 for the total weight of 16.9 mg; harpagide (5) (Venditti et al, 2016b(Venditti et al, , 2017a in mixture with forsythoside b (2) (Saracoğlu et al, 2002) in ratio 2:1 from the assembly of fractions 131-135 for the total weight of 5.6 mg. Given that not all compounds could be clearly detected from this chromatographic separation, another chromatographic separation was performed on the assembly of fractions 2-12 deriving from the first one for the total weight of 375.0 mg, using 16.0 g of silica gel (ratio 1:40 w/w) and a solution of dichloromethane and methanol at different concentrations as eluting system.…”

“…The initial ratio between these two solvents was 95/5 (v/v) but during the chromatographic run this was changed in order to let the elution of the most polar compounds passing to 9/1 (v/v), 8/2 (v/v), 7/3 (v/v) and 6/4 (v/v). From this chromatographic separation two further compounds were identified with the same methodology together with already evidenced compounds: cirsiliol ( 7) (Alwahsh et al, 2015;Venditti et al, 2017b) and β-arbutin ( 8) (Venditti et al, 2017a) in mixture among them in ratio 3:1 from the assembly of fractions 44-56 for the total weight of 19.9 mg, verbascoside (1) (Venditti et al, 2016a) as almost pure compound from the assembly of fraction 64-79 for the total weight of 16.4 mg.…”