Anti-inflammatory activity of verbascoside- and isoverbascoside-rich Lamiales medicinal plants.

Verbascoside and isoverbascoside are two active phenylethanoid glycosides mainly found in plants of the order Lamiales. This study analyzes the verbascoside and isoverbascoside levels and the total phenolic contents in the water and ethanolic extracts of 20 medicinal plants of the order Lamiales commonly used in Thailand. The related bioactivities, including the antioxidant activity via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reduction activity potential assays and anti-tyrosinase and -inflammatory activities via the cyclooxygenase and nitric oxide assays are also investigated. The extracts of several plant species, including Barleria prionitis, B. lupulina, Rhinacanthus nasutus, Orthosiphon aristatus, and Nicoteba betonica, exhibit high verbascoside and isoverbascoside content levels. The correlation analysis between the bioactive activities and the active compounds demonstrates a significant association between the verbascoside level in the water extracts and both the DPPH antioxidant activity and the nitric oxide level in the anti-inflammatory assays. This study provides the first report on the verbascoside and isoverbascoside quantification of several plant samples. The findings provide valuable insights for future research on lesser-studied plants possessing high verbascoside and isoverbascoside levels, which exhibit promising anti-inflammatory activities.

Phosphodiesterase-5 Inhibitory Activity of Canthin-6-One Alkaloids and the Roots of Eurycoma longifolia and Eurycoma harmandiana.

Eurycoma longifolia (EL) and Eurycoma harmandiana (EH) are natural medicinal plants belonging to the Simaroubaceae family, and are well-known for their ability to enhance male sexual performance. The present study investigated the phosphodiesterase-5 (PDE-5) inhibitory activity of intact roots of EL and EH. Additionally, canthin-6-one alkaloids, ß-carboline alkaloids, and quassinoids were also screened for PDE-5 inhibitory activity. We developed in vitro root and callus cultures of EL and EH to determine their PDE-5 inhibitory activity. Our results indicated that canthin-6-one alkaloids, which include canthin-6-one-9-O-ß-D-glucopyranoside, 9-methoxycanthin-6-one, canthin-6-one, and 9-hydroxycanthin-6-one, exhibited PDE-5 enzymatic inhibitory activity, with IC50 values of 2.86±0.23, 3.30±1.03, 4.31±0.52, and 4.66±1.13 µM, respectively. The ethanolic extract of the intact roots of EL and EH, and the in vitro root culture of EH had large amounts of canthin-6-one alkaloids (1.50±0.04, 2.12±0.03, and 3.48±0.08 mg/g dry weight, respectively), and showed potent PDE-5 inhibition. Our findings indicate that in vitro root cultures of EH may be used to replace intact plants, and canthin-6-one-9-O-ß-D-glucopyranoside should be further investigated for development as a health supplement.

HPLC-UV-Based Simultaneous Determination of Canthin-6-One Alkaloids, Quassinoids, and Scopoletin: The Active Ingredients in Eurycoma Longifolia Jack and Eurycoma Harmandiana Pierre, and Their Anti-Inflammatory Activities.

BACKGROUND: Quassinoids and canthin-6-one alkaloids are bioactive markers of Eurycoma longifolia (EL) and E. harmandiana (EH) and have been commercially utilized to treat inflammation and male infertility. OBJECTIVES: This study aims to reveal the contents of bioactive compounds and compare anti-inflammatory activities of these two species. METHODS: HPLC methods coupled with UV-Vis detection were developed and validated for the simultaneous analysis of the chemical profiles and their contents in EL and EH. The anti-inflammatory activities of both species were investigated using RAW 264.7 cell line. RESULTS: The HPLC methods provided a sensitivity (LOD) of 0.02-0.05 µg/mL for the eight bioactive compounds (canthin-6-one alkaloids, quassinoids, and scopoletin) with high precision (% relative standard deviation (RSD) ≤6.48) and recoveries between 80.0 and 120%. The chaparrinone: eurycomanone ratio was high in EH, whereas EL had a higher ratio of eurycomanone: chaparrinone than EH. The contents of total canthin-6-one alkaloids, quassinoids, and scopoletin were 0.01-0.75, 0.19-1.54, and 0.01-0.28 mg/g, respectively, in EL roots and 0.12-1.80, 7.05-9.26, and 0.02 mg/g, respectively, in EH roots. The anti-inflammatory effects of EL and EH extracts varied among the samples due to the variation in their chemical constituents. CONCLUSIONS: In summary, our study indicated that chaparrinone was the major compound in EH. EH exhibited anti-inflammatory activity to the same extent as EL. HIGHLIGHTS: EH and EL extracts were analyzed using developed HPLC-UV methods, revealing a high concentration of chaparrinone in EH, and an anti-inflammatory assay indicated that EH had a potency comparable to that of EL.

Phenylethanoid and flavone glycosides from Ruellia tuberosa L.

A new phenylethanoid glycoside, isocassifolioside (8), and two new flavone glycosides, hispidulin 7-O-α-L-rhamnopyranosyl-(1'″ → 2″)-O-ß-D-glucuronopyranoside (11) and pectolinaringenin 7-O-α-L-rhamnopyranosyl-(1'″ → 2″)-O-ß-D-glucuronopyranoside (12) were isolated from the aerial portions of Ruellia tuberosa L., together with verbascoside (1), isoverbascoside (2), nuomioside (3), isonuomioside (4), forsythoside B (5), paucifloside (6), cassifolioside (7), hispidulin 7-O-ß-D-glucuronopyranoside (9) and comanthoside B (10). The structure elucidations were based on analyses of chemical and spectroscopic data including 1D- and 2D-NMR. The isolated compounds 1-12 exhibited radical scavenging activity using ORAC assay.

Unprecedented furan-2-carbonyl C-glycosides and phenolic diglycosides from Scleropyrum pentandrum.

Five unprecedented furan-2-carbonyl C-glycosides, scleropentasides A-E, and two phenolic diglycosides, 4-hydroxy-3-methoxybenzyl 4-O-ß-D-xylopyranosyl-(1→6)-ß-D-glucopyranoside and 2,6-dimethoxy-p-hydroquinone 1-O-ß-D-xylopyranosyl-(1→6)-ß-d-glucopyranoside, were isolated from leaves and twigs of Scleropyrum pentandrum together with potalioside B, luteolin 6-C-ß-D-glucopyranoside (isoorientin), apigenin 8-C-ß-D-glucopyranoside (vitexin), apigenin 6,8-di-C-ß-D-glucopyranoside (vicenin-2), apigenin 6-C-α-L-arabinopyranosyl-8-C-ß-D-glucopyranoside (isoschaftoside), apigenin 6-C-ß-D-glucopyranosyl-8-C-ß-D-xylopyranoside, adenosine and l-tryptophan. Structure elucidations of these compounds were based on analyses of chemical and spectroscopic data, including 1D and 2D NMR. In addition, the isolated compounds were evaluated for their radical scavenging activities using both DPPH and ORAC assays.

L-(-)-(N-trans-cinnamoyl)-arginine, an acylamino acid from Glinus oppositifolius (L.) Aug. DC.

An amino acid derivative, L-(-)-(N-trans-cinnamoyl)-arginine, was isolated from the whole plant of Glinus oppositifolius (L.) Aug. DC. along with kaempferol 3-O-galactopyranoside, isorhamnetin 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-galactopyranoside, vitexin, vicenin-2, adenosine and L-phenylalanine. The structure determinations were based on analyses of chemical and spectroscopic methods.

Antioxidant, antibacterial and antigiardial activities of Walsura robusta Roxb.

Walsura robusta Roxb. (Family: Meliaceae) is a well-known multi-purpose medicinal plant, and has been employed for a wide range of disease conditions without documented scientific data. In the current study, four pure isolated compounds, 3,4,5-trimethoxyphenyl beta-D-glucopyranoside (1), turpinionoside A (2), (+)-lyoniresinol 3alpha-O-beta-D-glucopyranoside (3) and (-)-lyoniresinol 3alpha-O-beta-D-glucopyranoside (4), were isolated from the leaves and twigs of W. robusta. Biological evaluation for free radical scavenging, antibacterial and antigiardial activities was performed. We investigated antioxidant effects of the crude extracts as well as the isolated compounds using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), hydroxyl radical (OH), and superoxide anion (O(2)) scavenging assays. Three phenolic glucosides (1, 3 and 4) were found to possess strong antioxidant activity. They scavenged DPPH(*) with IC(50) values in the range of 51.5-86.6 microM. We also detected the superoxide dismutase-like activities in compounds 3 and 4 which are lignan glucosides, demonstrating potent superoxide scavenging activity with IC(50) values in the range of 0.8 and 0.7 microM, respectively. Other biological activities including antibacterial and antigiardial assays were carried out. Preliminary results demonstrated that most extracts, except the diethyl ether extract, exhibited inhibition zones against all Gram-positive bacteria including Bacillus cereus, Staphylococcus aureus, Streptococcus mutans, and S. pyogenes. Aqueous extracts of this plant species could inhibit Gram-positive and some Gram-negative bacteria such as Escherichia coli, Salmonella typhi and Shigella sonnei. However, the determination of minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of W. robusta on all tested bacterial strains showed only weak activity, and their MBCs were greater than 25 mg mL(-1). For antigiardial activity, incubation with 2 x 10(5) trophozoites mL(-1) of the culture medium with the crude extracts at concentration ranged from 31.25 to 1000 microg mL(-1) demonstrated no activity (MIC > 1000 microg mL(-1)).

Evaluation of chikusetsusaponin IVa isolated from Alternanthera philoxeroides for its potency against viral replication.

Chikusetsusaponin IVa and calenduloside E were isolated from the whole plant of Alternanthera philoxeroides (Mart.) Griseb (Amaranthaceae) and evaluated for their antiviral activities. Chikusetsusaponin IVa showed antiviral activities against HSV-1, HSV-2, human cytomegalovirus, measles virus, and mumps virus with selectivity indices (CC (50)/IC (50)) of 29, 30, 73, 25, and 25, respectively. On the other hand, calenduloside E showed no antiviral effects against any of the viruses tested. The mode of HSV-2 action of chikusetsusaponin IVa was determined under different experimental conditions. The anti-HSV-2 target of the compound might be mainly related to direct inactivation of virus particles and to the inhibition of release of progeny viruses from infected cells, but it is not related to inhibition of viral attachment, cell penetration, and viral protein synthesis. This compound also provided in vivo efficacy in a mouse model of genital herpes caused by HSV-2. These results demonstrate that chikusetsusaponin IVa might be a candidate of antiherpetic agents.

Chemical constituents from Oldenlandia corymbosa L. of Thai origin.

From the whole plants of Oldenlandia corymbosa of Thai origin, ten compounds have been isolated and elucidated as geniposide, 6 alpha-hydroxygeniposide, scandoside methyl ester (6 beta-hydroxygeniposide), asperulosidic acid, deacetylasperuloside, asperuloside, 10-O-benzoylscandoside methyl ester, 10-O-p-hydroxybenzoylscandoside methyl ester, (+)-lyoniresinol-3 alpha-O-beta-glucopyranoside, and rutin. Their structures were determined on the basis of spectroscopic data.

Megastigmane and flavone glycosides from Strophioblachia fimbricalyx Boerl.

Three megastigmane glucosides, bridelionoside B, ampelopsisionoside and 3-hydroxy-5,6-epoxy-beta-ionol 9-O-beta-D-glucopyranoside, together with three flavone glycosides, apigenin 7-O-beta-D-glucopyranoside, isovitexin and spinosin, were isolated from the aerial portions of Strophioblachia fimbricalyx. The structure determinations were based on physical data and spectroscopic evidence.

Tricalysiosides P-U: Ent-kaurane glucosides and a labdane glucoside from leaves of Tricalysia dubia OHWI.

Further extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of Tricalysia dubia afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with a known megastigmane glucoside, sammangaoside B (1), and monoterpene glucosides (2, 3). The structures of the new compounds were elucidated by analyses of one- and two-dimensional NMR spectroscopic data. The absolute configuration of the 9-position of sammangaoside B was revised to S and its total stereochemistry was established by the modified Mosher's method.

Dolichandroside, a new phenolic triglycoside from Dolichandrone serrulata (DC.) Seem.

A new phenolic triglycoside, dolichandroside, was isolated from the branches of Dolichandrone serrulata together with decaffeoyl-verbascoside, verbascoside, isoverbascoside, markhamioside A, 2''-O-apiosylverbascoside, luteoside B and ixoside. The structure elucidations were based on analyses of spectroscopic data.

Acetophenone diglycosides from Erythroxylum cambodianum.

Two new acetophenone diglycosides, erythroxylosides A and B, were isolated from the aerial portion of Erythroxylum cambodianum together with (+)-catechin, (-)-epicatechin, quercetin 3-O-rutinoside, (3S,5R,6R,7E,9S-megastigman-7-ene-3,5,6,9-tetrol 3-O-beta-D-glucopyranoside and citroside A. The structural elucidations were based on analyses of chemical and spectroscopic data.

Aliphatic alcohol and iridoid glycosides from Asystasia intrusa.

An aliphatic alcohol glycoside (asystoside) and an iridoid diglucoside (3'-O-beta-D-glucopyranosyl-catalpol) were isolated from the aerial part of Asystasia intrusa along with benzyl beta-D-glucopyranoside, zizybeoside I, (6S,9R)-roseoside, verbascoside, ehrenoside, 6beta-hydroxyantirrhide, angeloside, catalpol, ajugol, 6-deoxycatalpol, and scutellarioside II. The structural elucidations were based on analyses of physical and spectroscopic data.

Phenylethanoid and iridoid glycosides from the Thai medicinal plant, Barleria strigosa.

A phenylethanoid (4-hydroxyphenylethyl 4-O-beta-D-glucopyranosyl-(1-->3)-O-alpha-L-rhamnopyranoside) and an iridoid (10-O-trans-coumaroyl-eranthemoside) were isolated from an entire Barleria strigosa plant together with verbascoside, isoverbascoside, decaffeoylverbascoside, (+)-lyoniresinol 3alpha-O-beta-D-glucoside, apigenin 7-O-alpha-L-rhamnosyl-(1-->6)-O-beta-D-glucoside, 7-O-acetyl-8-epi-loganic acid and (3R)-1-octen-3-ol-3-O-beta-D-xylosyl-(1-->6)-beta-D-glucoside. The structural elucidations were based on analyses of physical and spectroscopic data.

Pregnane and pregnane glycosides from the Malagasy plant, Cynanchum aphyllum.

A new 8,14-seco-pregnane type of steroid called cynaphyllogenin and its eight glycosides, cynaphyllosides A-H, were isolated from the aerial parts of Cynanchum aphyllum. The structures of these compounds were elucidated based on chemical and spectroscopic evidence.