TLC bioautography-guided isolation of antioxidants from fruit of Perilla frutescens var. acuta

Guided isolation through bioautography on TLC using 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) as a detection reagent led to the isolation of four antioxidant compounds from fruit of Perilla frutescens var. acuta. These compounds were identified as rosmarinic acid (1), luteolin (2), apigenin (3), and chrysoeriol (4), by means of UV, NMR, and ESI MS. All the compounds were isolated for the first time from the fruit of the plant. Compounds 1 and 2 showed significant DPPH scavenging capacities, with IC₅₀ values of 8.61 and 7.50 μM, respectively. Further quantitative HPLC analysis confirmed that compounds 1-4 are the predominant contributors to the free radical scavenging activity of the extract of P. frutescens var. acuta.     

Identification of antioxidants from rhizome of Davallia solida

Davallia solida rhizome has long been used as an herb tonic to treat osteoporosis, arthralgia, and arthritis. The aqueous extract of D. solida rhizome contains a high content of phenolic compounds [210.8 ± 4.6 mg catechin equivalents (CE)/g dry weight] and shows a strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (IC₅₀ = 15.93 ± 1.21 μg dry weight/ml). Further solvent partition of the aqueous extract yielded chloroform, n-butanol, and water layers. Among them, n-butanol layer has the highest phenol content (806.3 ± 12.3 mg CE/g dry weight) and DPPH scavenging potential (IC₅₀ = 3.93 ± 0.31 μg dry weight/ml). Isolation and purification from the n-butanol layer identified 12 compounds. They included four new compounds: 3′-O-p-hydroxybenzoylmangiferin (1), 4′-O-p-hydroxybenzoylmangiferin (2), 6′-O-p-hydroxybenzoylmangiferin (3), and 3-O-p-hydroxybenzoylmangiferin (4); as well as eight known compounds: mangiferin (5), 2-C-β-d-xylopyranosyl-1,3,6,7-tetrahydroxyxanthone (6), 4β-carboxymethyl-(−)-epicatechin (7), 4β-carboxymethyl-(−)-epicatechin methyl ester (8), eriodictyol (9), eriodictyol-8-C-β-d-glucopyranoside (10), icariside E₅ (11), and icariside E₃ (12). DPPH scavenging and Trolox equivalent antioxidant capacity (TEAC) analyses revealed that the most potent antioxidants are 1, 2, and 3, which exerted more than triple activity as compared with the positive controls, α-tocopherol and Trolox.     

Antioxidant triterpenoids from the stems of Momordica charantia

A new multiflorane triterpenoid and two new cucurbitane triterpenoids were isolated from the stems of Momordica charantia. The structures of the new compounds were elucidated by spectroscopic methods. These three new compounds, 1, 2 and 3 displayed ABTS radical cation scavenging activity with IC₅₀ values of 268.5 ± 7.9, 352.1 ± 11.5 and 458.9 ± 13.0 μM, respectively and an inhibitory effect on xanthine oxidase (XO) activity with IC₅₀ values of 142.3 ± 30.2, 36.8 ± 20.5 and 124.9 ± 8.3 μM, respectively. This finding indicated that 1–3 can be used as antioxidants.     

Anti-inflammatory effects of compounds from Kaempferia parviflora and Boesenbergia pandurata

Kaempferia parviflora and Boesenbergia pandurata are perennial herbs in the Zingiberaceae family. The rhizomes of these two plants have been used as food ingredients and in Thai traditional medicine for treatment of several inflammatory-related diseases, such as gout, allergy, apthous ulcer and peptic ulcer. The compounds isolated from the rhizomes of K. parviflora and B. pandurata were, therefore, examined for their inhibitory activities against nitric oxide (NO) production. For K. parviflora, compound 5 (5-hydroxy-3,7,3′,4′-tetramethoxyflavone) exhibited the highest activity against the NO inhibitory effect, with an IC₅₀ value of 16.1 μM, followed by 4 (IC₅₀ = 24.5 μM) and 3 (IC₅₀ = 30.6 μM). Regarding the NO inhibitory activity of B. pandurata, compound 2 (panduratin A) displayed the most potent effect with an IC₅₀ value of 5.3 μM, followed by 3 (hydroxypanduratin A, IC₅₀ = 13.3 μM) and 7 (cardamonin, IC₅₀ = 24.7 μM), respectively. The 5-hydroxy-3,7,3′,4′-tetramethoxyflavone (5), panduratin A (2) and hydroxypanduratin A (3), were also tested on prostaglandin E₂ (PGE₂) and tumour necrosis factor-alpha (TNF-α) production. 5-Hydroxy-3,7,3′,4′-tetramethoxyflavone (5) exhibited a potent inhibitory effect on PGE₂ production (IC₅₀ = 16.3 μM), but a mild effect on TNF-α (IC₅₀ > 100 μM). Panduratin A and hydroxypanduratin A showed strong activity against PGE₂ with IC₅₀ values of 10.5 and 12.3 μM, respectively, and a moderate effect on TNF-α (IC₅₀ = 60.3 and 57.3 μM, respectively). This study indicated that compound 5 (5-hydroxy-3,7,3′,4′-tetramethoxyflavone) is responsible for anti-inflammatory activity of K. parviflora, while 2 (panduratin A) and 3 (hydroxypanduratin A), the prenylated chalcones, are responsible for that of B. pandurata.     

Abietane diterpenoids of Rosmarinus officinalis and their diacylglycerol acyltransferase-inhibitory activity

Inhibition of acyl CoA:diacylglycerol acyltransferase (DGAT) has been proposed as one of the drug targets for treating obesity and type 2 diabetes. Bioassay-guided fractionation of the MeOH-soluble extract of Rosmarinus officinalis yielded two new diacylglycerol acyltransferase (DGAT) inhibitory-abietane diterpenoids, 7β-hydroxy-20-deoxo-rosmaquinone (1) and 7β-methoxy-20-deoxo-rosmanol (2), along with six known components, carnosol (3), 7α-methoxyrosmanol (4), 7β-methoxyrosmanol (5), 12-methoxy-canosic acid (6), rosmanol (7), and rosmadial (8). Compounds 1–8 inhibited DGAT1 activity, with the IC₅₀ values ranging from 39.5 ± 0.6 to 144.2 ± 3.1 μM. In particular, carnosol (3), which is one of the major compounds of MeOH-soluble extract of R. officinalis exhibits inhibition of de novo intracellular triacylglycerol synthesis in human hepatocyte HepG2 cells.     

New benzenoids and anti-inflammatory constituents from Zanthoxylum nitidum

Zanthoxylum nitidum is commercially used in healthcare products for the improvement of tooth condition. Its fruit is also used as a spice. Three new benzenoids, (E)-4-(4-hydroxy-3-methylbut-2-enyloxy)benzaldehyde (1), (E)-methyl 3-(4-((E)-4-hydroxy-3-methylbut-2-enyloxy)phenyl)acrylate (2), and (Z)-methyl 3-(4-((E)-4-hydroxy-3-methylbut-2-enyloxy)phenyl)acrylate (3), have been isolated from the stem wood of Z. nitidum, together with 17 known compounds (4–20). The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 8–10, 13, 14, 17, and 18 exhibited inhibition (IC₅₀ ? 7.95 μg/ml) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). Compounds 7–9, 13, 14, and 17 inhibited fMLP/CB-induced elastase release with IC₅₀ values ?7.45 μg/ml.     

New coumarins and anti-inflammatory constituents from Zanthoxylum avicennae

Zanthoxylum avicennae is commercially used as healthcare products for the improvement of chronic hepatitis and rheumatism. Its fruit is also used as a spice. Five new coumarins, 5′-methoxyauraptene (1), 6,5′-dimethoxyauraptene (2), 5′-methoxycollinin (3), 7-((2′E,5′E)-7′-methoxy-3′,7′-dimethylocta-2′,5′-dienyloxy)coumarin (4), and 6-methoxy-7-((2′E,5′E)-7′-methoxy-3′,7′-dimethylocta-2′,5′-dienyloxy)coumarin (5), have been isolated from the leaves of Z. avicennae, together with 15 known compounds (6–20). The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 6, 9–15, and 18 exhibited inhibition (IC₅₀ ? 8.29 μg/ml) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). Compounds 6, 10, 12, 14, and 18 inhibited fMLP/CB-induced elastase release with IC₅₀ values ?6.30 μg/ml.     

Sesquiterpenes from the rhizome of Curcuma longa with inhibitory activity on superoxide generation and elastase release by neutrophils

Six new sesquiterpenes, curculonone A (1), curculonone B (2), curculonone C (3), curculonone D (4), 6α-hydroxycurcumanolide A (5), and 1,10-dehydro-10-deoxy-9-oxozedoarondiol (6), have been isolated from the rhizome of Curcuma longa, together with 19 known compounds. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 2, 5, 12, 15, 16, and 23 exhibited inhibition (IC₅₀ ? 18.22 μM) of superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Compounds 5, 12–16, and 23 inhibited fMLP/CB-induced elastase release with IC₅₀ values ? 14.28 μM.     

Abietane diterpenoids from Isodon lophanthoides var. graciliflorus and their cytotoxicity

Seven new (1–7) and three known (8–10) abietane diterpenoids were isolated from the methanolic extract of the aerial parts of Isodon lophanthoides var. graciliflorus (Lamiaceae), a folk Chinese medicine and an herb for functional beverages. They were identified as 16-acetoxylsugiol (1), graciliflorin E (2), graciliflorin F (3), 15-O-methylgraciliflorin F (4), 15-hydroxy-20-deoxocarnosol (5), 3β-hydroxysempervirol (6), 15-hydroxy-1-oxosalvibretol (7), abieta-8,11,13-triene-14,19-diol (8), 6,12,15-trihydroxy-5,8,11,13-abietatetraen-7-one (9), and 3α-hinokiol (10) based on the spectroscopic data including COSY (correlated spectroscopy), HMBC (heteronuclear multiple bond correlation), and HR-ESI-MS (high-resolution electrospray ionization mass spectrometry). All the compounds except 10 were obtained from I. lophanthoides for the first time. Compounds 1, 2, 5, 6, 8, and 9 exhibited in vitro cytotoxicity against A549 (human lung adenocarcinoma), MCF-7 (human breast adenocarcinoma), and HeLa (human cervical carcinoma) cell lines with the IC₅₀ values of 1.79–52.67 μM.     

Constituents of Sideritis syriaca. ssp. syriaca (Lamiaceae) and their antioxidant activity

The aerial parts of Sideritis syriaca ssp. syriaca (Lamiaceae) were extracted, after defatting, with diethyl ether, ethyl acetate and n-butanol. The antioxidant activities of the extracts were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picryl hydrazyl (DPPH) and Co(II) EDTA-induced luminol chemiluminescence. In both model systems the ethyl acetate extract was the most effective. Phytochemical analysis of ethyl acetate extract showed the presence of two new isomeric compounds (1 and 1′), identified as 1-rhamnosyl, 1-coumaroyl, dihydrocaffeoyl, protocatechuic tetraester of quinic acid, as well as chlorogenic acid (2), apigenin 7-O-glucoside (3), apigenin (4), 4′-O-methylisoscutellarein 7-O-[6′′′-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (5), isoscutellarein 7-O-[6′′′-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (6), 4′-O-methylisoscutellarein 7-O[β-d-allopyranosyl-(1 → 2)-β-d-glucopyranoside] (7) and 4′-O-methylisoscutellarein 7-O-[β-d-allopyranosyl-(1 → 2)-6′′-O-acetyl-β-d-glucopyranoside] (8). The above compounds were identified by spectroscopic methods.     

Biological activities of flavonoids from pathogenic-infected Astragalus adsurgens

The present study was aimed at the identification of biological components from pathogenic-infected Astragalus adsurgens with an activity-guided purification process. Fifteen flavonoids were obtained from the most active ethyl acetate fraction and identified as astradsurnin (1), a new chalcone derivative, together with fourteen known flavonoids (2-15). These compounds were tested for antibacterial activities against five bacteria and cytotoxic activities against two selected cancer cells. Within the series of flavonoids tested, compounds 4 and 15 were the most active against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Erwinia carotovora and Bacillus subtilis with MICs ranging from 7.8 to 31.3 μg/ml. Moreover, compounds 4 and 5 exhibited moderate activity against HL-60 and SMMC-7721 cells with IC₅₀ values between 5 and 10 μg/ml. To our knowledge, this is the first time that it has been reported on the biological and chemical study of A. adsurgens infected by Embellisia astragali.     

Removing gluconic acid by using different treatments with a Schizosaccharomyces pombe mutant: Effect on fermentation byproducts

Three different treatments involving inoculation with Schizosaccharomyces pombe YGS-5 and Saccharomyces cerevisiae G1 strains were tested with a view to reducing the amount of gluconic acid in synthetic medium. The treatments involved (a) simultaneous inoculation with S. cerevisiae and S. pombe (SpSc); (b) depletion of gluconic acid with S. pombe and subsequent inoculation with S. cerevisiae following removal of S. pombe from the medium (Sp − Sp + Sc); and (c) as (b) but without removing S. pombe from the medium (Sp + Sc). The results thus obtained were compared with those for a control treatment involving fermentation with S. cerevisiae alone (Sc). The amounts of volatile compounds quantified in the fermented media were similar with the treatments where gluconic acid was previously depleted (viz.Sp − Sp + Sc and Sp + Sc). Amino acids were used in large amounts by S. pombe during removal of gluconic acid; this affected subsequent fermentation by S. cerevisiae and the formation of byproducts. Based on the gluconic acid uptake, fermentation kinetics, volatile composition and absence of off-flavours in the fermented media, both treatments (Sp − Sp + Sc and Sp + Sc) can be effectively used in winemaking processes to remove gluconic acid from must prior to fermentation.