Isolation, Characterization and In Silico Studies of Secondary Metabolites from the Whole Plant of Polygala inexpectata Pesmen & Erik.

Polygala species are frequently used worldwide in the treatment of various diseases, such as inflammatory and autoimmune disorders as well as metabolic and neurodegenerative diseases, due to the large number of secondary metabolites they contain. The present study was performed on Polygala inexpectata, which is a narrow endemic species for the flora of Turkey, and resulted in the isolation of nine known compounds, 6,3'-disinapoyl-sucrose (1), 6-O-sinapoyl,3'-O-trimethoxy-cinnamoyl-sucrose (tenuifoliside C) (2), 3'-O-(O-methyl-feruloyl)-sucrose (3), 3'-O-(sinapoyl)-sucrose (4), 3'-O-trimethoxy-cinnamoyl-sucrose (glomeratose) (5), 3'-O-feruloyl-sucrose (sibiricose A5) (6), sinapyl alcohol 4-O-glucoside (syringin or eleutheroside B) (7), liriodendrin (8), and 7,4'-di-O-methylquercetin-3-O-ß-rutinoside (ombuin 3-O-rutinoside or ombuoside) (9). The structures of the compounds were determined by the spectroscopic methods including 1D-NMR (1H NMR, 13C NMR, DEPT-135), 2D-NMR (COSY, NOESY, HSQC, HMBC), and HRMS. The isolated compounds were shown in an in silico setting to be accommodated well within the inhibitor-binding pockets of myeloperoxidase and inducible nitric oxide synthase and anchored mainly through hydrogen-bonding interactions and π-effects. It is therefore plausible to suggest that the previously established anti-inflammatory properties of some Polygala-derived phytochemicals may be due, in part, to the modulation of pro-inflammatory enzyme activities.

Chemical constituents of two sages with free radical scavenging activity.

From the aerial parts of Salvia trichoclada Bentham and S. verticillata L. one new and two known phenolic acids, 3-(3',4'-dihydroxyphenyl)-2-hydroxymethyl propionic acid (1), 3-(3',4'-dihydroxyphenyl) lactic acid (2), and rosmarinic acid (3); two flavonoids, apigenin 4'-methyl ether 7-O-glucuronide (4), and luteolin 7-O-beta glucuronide (5); two lupan type triterpene aglycones, lupeol (6), and 30-hydroxylup-20 (29)-en-3-on (7); an oleanane-type triterpene acid, oleanolic acid (8); and an ursan-type triterpene acid, ursolic acid (9) were isolated. The structures of the compounds were elucidated by spectroscopic analysis. Different extracts of the plants were examined for their free radical scavenging activities by DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay. Some of the polar extracts showed high free radical scavenging activity.

Cycloartane glycosides from Astragalus campylosema Boiss. ssp. campylosema.

Four cycloartane glycosides, 3-O-[alpha-l-arabinopyranosyl-(1-->2)-beta-d-xylopyranosyl]-3beta,6alpha,16beta,23alpha,25-pentahydroxy-20(R),24(S)-epoxycycloartane (1), 3-O-[alpha-l-arabinopyranosyl-(1-->2)-beta-d-xylopyranosyl]-16-O-hydroxyacetoxy-23-O-acetoxy-3beta,6alpha,25-trihydroxy-20(R),24(S)-epoxycycloartane (2), 3-O-[alpha-l-arabinopyranosyl-(1-->2)-beta-d-xylopyranosyl]-3beta,6alpha,23alpha,25-tetrahydroxy-20(R),24(R)-16beta,24;20,24-diepoxycycloartane (3), 3-O-[alpha-l-arabinopyranosyl-(1-->2)-beta-d-xylopyranosyl]-25-O-beta-d-glucopyranosyl-3beta,6alpha,16beta,25-tetrahydroxy-20(R),24(S)-epoxycycloartane (4), along with three known cycloartane glycosides were isolated from the MeOH extract of the roots of Astragalus campylosema ssp. campylosema. Their structures were established by the extensive use of 1D- and 2D-NMR experiments along with ESIMS and HRMS analysis. The occurrence of the hydroxyl function at position 23 (1-2) and of the ketalic function at C-24 (3) are very unusual findings in the cycloartane class.

Crypthophilic acids A, B, and C: resin glycosides from aerial parts of Scrophularia crypthophila.

The water-soluble part of the methanolic extract from the aerial parts of Scrophularia crypthophila, through chromatographic methods, yielded three new resin glycosides, crypthophilic acids A - C (1-3). Compounds 1-3 are tetraglycosides of (+)-3S,12S-dihydroxypalmitic acid. The structures of these and 10 known compounds were elucidated by spectroscopic and chemical means. All natural resin glycosides known so far have been obtained from Convolvulaceae plants; this is the first report of such glycosides from another, taxonomically unrelated family (Scrophulariaceae).

Inhibiting activities of the secondary metabolites of Phlomis brunneogaleata against parasitic protozoa and plasmodial enoyl-ACP Reductase, a crucial enzyme in fatty acid biosynthesis.

Anti-plasmodial activity-guided fractionation of Phlomis brunneogaleata (Lamiaceae) led to the isolation of two new metabolites, the iridoid glycoside, brunneogaleatoside and a new pyrrolidinium derivative (2 S,4 R)-2-carboxy-4-( E)- p-coumaroyloxy-1,1-dimethylpyrrolidinium inner salt [(2 S,4 R)-1,1-dimethyl-4-( E)- p-coumaroyloxyproline inner salt]. Moreover, a known iridoid glycoside, ipolamiide, six known phenylethanoid glycosides, verbascoside, isoverbascoside, forsythoside B, echinacoside, glucopyranosyl-(1-->G (i)-6)-martynoside and integrifolioside B, two flavone glycosides, luteolin 7- O-beta- D-glucopyranoside ( 10) and chrysoeriol 7- O-beta- D-glucopyranoside ( 11), a lignan glycoside liriodendrin, an acetophenone glycoside 4-hydroxyacetophenone 4- O-(6'- O-beta- D-apiofuranosyl)-beta- D-glucopyranoside and three caffeic acid esters, chlorogenic acid, 3-O-caffeoylquinic acid methyl ester and 5- O-caffeoylshikimic acid were isolated. The structures of the pure compounds were elucidated by means of spectroscopic methods (UV, IR, MS, 1D and 2D NMR, [alpha] (D)) and X-ray crystallography. Compounds 10 and 11 were determined to be the major anti-malarial principles of the crude extract (IC (50) values of 2.4 and 5.9 micrograms/mL, respectively). They also exhibited significant leishmanicidal activity (IC (50) = 1.1 and 4.1 micrograms/mL, respectively). The inhibitory potential of the pure metabolites against plasmodial enoyl-ACP reductase (FabI), which is the key regulator of type II fatty acid synthases (FAS-II) in P. falciparum, was also assessed. Compound 10 showed promising FabI inhibiting effect (IC (50) = 10 micrograms/mL) and appears to be the first anti-malarial natural product targeting FabI of P. falciparum.