Antileishmanial amides and lignans from <Emphasis Type="Italic">Piper cubeba</Emphasis> and <Emphasis Type="Italic">Piper retrofractum</Emphasis>

The n-hexane, ethyl acetate, methanol, and acetone extracts of Piper cubeba Linn. and P. retrofractum Vahl. (Piperaceae) were evaluated in vitro against promastigotes of Leishmania donovani, and all exhibited significant in vitro activity at 100 μg/ml. Two lignans, cubebin and hinokinin, were isolated from the hexane extract of P. cubeba; and one bis-epoxy lignan, (−)-sesamin, and two amides, pellitorine and piplartine, were isolated from the hexane and methanol extracts of P. retrofractum. Cubebin and piplartine showed significant antileishmanial activity in vitro at 100 μM and were further tested in vivo in a hamster model of visceral leishmaniasis. Piplartine showed activity at 30 mg/kg dose. This is the first report of antileishmanial activity of these two plants and their isolated constituents. NIPER Communication No. 395.     

Secoiridoid glycosides from the leaves of <Emphasis Type="Italic">Hydrangea macrophylla</Emphasis> subsp. <Emphasis Type="Italic">serrata</Emphasis>

Seven secoiridoid glycosides, secologanin dimethyl acetal (1), n-butyl vogeloside (2), n-butyl epi-vogeloside (3), (7R)-n-butyl morroniside (4), hydrangenoside A (5), hydrangenoside C (6), and hydrangenoside A dimethyl acetal (7), have been isolated from the leaves of Hydrangea macrophylla subsp. serrata (Thunb.) Makino (Saxifragaceae). The structures were elucidated on the basis of spectral data.     

Antitubercular triterpenes and phytosterols from <Emphasis Type="Italic">Pandanus tectorius </Emphasis>Soland. var. <Emphasis Type="Italic">laevis</Emphasis>

Bioassay-guided chromatographic purification of the antitubercular chloroform extract of Pandanus tectorius Soland. var. laevis leaves afforded a new tirucallane-type triterpene, 24,24-dimethyl-5β-tirucall-9(11),25-dien-3-one (1), squalene and a mixture of the phytosterols stigmasterol and β-sitosterol. Microplate Alamar Blue Assay (MABA) showed that 1 inhibited the growth of Mycobacterium tuberculosis H₃₇Rv with a MIC of 64 μg/mL, while squalene and the sterol mixture have MICs of 100 and 128 μg/mL, respectively.     

Monoterpene glycoside and flavonoids from <Emphasis Type="Italic">Blumea lacera</Emphasis>

The dichloromethane extract of air-dried leaves of Blumea lacera (Asteraceae) afforded α-pinene-7β-O-β-d-2,6-diacetylglucopyranoside (1), 5,4′-dihydroxy-6,7,3′-trimethoxyflavone (2), and 3,5,4′-trihydroxy-6,7,3′-trimethoxyflavone (3). Compounds 1–3 showed moderate activity against Candida albicans, low activity against Trichophyton mentagrophytes, and were inactive against Aspergillus niger. Compounds 1 and 3 indicated low activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus and were inactive against Bacillus subtilis, while 2 was inactive against all four bacteria tested.     

Chemical studies on monoterpenoid indole alkaloids from medicinal plant resources <Emphasis Type="Italic">Gelsemium</Emphasis> and <Emphasis Type="Italic">Ophiorrhiza</Emphasis>

We have proved that the plant of origin of “Yakatsu”, one of the ancient medicines stored in Shosoin Repository, is Gelsemium elegans (Loganiaceae). Exhaustive investigation of the alkaloids in this plant as well as its closely related plant, G. sempervirens, resulted in the isolation of more than 50 compounds, including new gelsedine-, sarpagine-, and yohimbane-type alkaloids. Pharmacological study of representative and new Gelsemium alkaloids revealed that the gelsedine-type alkaloids exhibit potent cytotoxic activity against the A431 human epidermoid carcinoma cell line. It was found that Ophiorrhiza pumila (Rubiaceae) produces a remarkable anti-tumor alkaloid, camptothecin, and its related alkaloids, including new compounds that might be the biogenetic precursors of camptothecin. Chemical investigation of callus cultures, regenerated plants, and hairy roots of O. pumila revealed that the regenerated plants and the hairy roots produce almost the same alkaloids, including camptothecin, as do the wild-type plants.     

Variation in growth and diterpene lactones among field-cultivated <Emphasis Type="Italic">Andrographis paniculata</Emphasis>

Seed-raised Andrographis paniculata (Acanthaceae) from 28 accessions were grown in a randomized complete block design to determine morphological characteristics and diterpene contents. The average amount of dried leaves per individual was between 2.13 and 8.23 g. The average andrographolide content varied from 12.44 to 33.52 mg/g dried leaves and 14-deoxy-11,12-didehydroandrographolide content varied from 0.23 to 2.08 mg/g dried leaves. The differences in phytomass and diterpene contents among the plants from different accessions were statistically significant. Furthermore, we isolated the elite individual plants containing high amounts of andrographolide and 14-deoxy-11,12-didehydroandrographolide (up to 52.57 and 3.46 mg/g dried leaves, respectively). The results indicated those populations are potentially important sources for breeding and improvement of cultivars.     

A new phenylethanoid glycoside from the fruits of <Emphasis Type="Italic">Callicarpa japonica</Emphasis> Thunb. var. <Emphasis Type="Italic">luxurians</Emphasis> Rehd.

A new phenylethanoid glycoside, named acetyl forsythoside B (1), was isolated from the fruits of Callicarpa japonica Thunb. var. luxurians Rehd. (Verbenaceae) along with forsythoside B (2), brandioside (3), poliumoside (4), actioside (5), and apigenin 7-galacturonide (6). The structures of 1–6 were determined on the basis of spectroscopic data. In addition, the antioxidative activity of 1–4 and 6 was evaluated by the ferric thiocyanate method. All of the tested compounds except 6 exhibited almost the same activity as 3-tert-butyl-4-hydroxyanisole. The radical-scavenging effect of 1–6 on the stable free radical 1,1-diphenyl-2-picrylhydrazyl was also examined. Compounds 1–5 showed almost twice the activity compared to α-tocopherol.     

Free-radical scavenging activity of <Emphasis Type="Italic">Bergia suffruticosa</Emphasis> (Delile) Fenzl

Bergia suffruticosa (Family Elatinaceae) is an important Indian medicinal plant, traditionally used to repair bones and applied on sores. The plant has not been studied much. Preliminary phytochemical screening of the plant showed the presence of high amount of phenolics, tannins and flavonoids. Subsequent quantification showed the presence of 8.8% w/w phenolics (calculated as gallic acid), and 7.5% w/w tannins. This high amount of tannins and phenolics prompted us to evaluate its antioxidant activity. We studied the antioxidant activity of B. suffruticosa whole plant in three in vitro models: DPPH radical scavenging activity, superoxide scavenging activity and measurement of reducing power. Methanolic extract of whole plant of B. suffruticosa showed a very good DPPH radical scavenging activity (EC₅₀ of 13.1 μg) and superoxide scavenging activity (EC₅₀ of 139.4 μg) in a dose-dependent manner. The extract showed dose-dependent reduction ability (Fe³⁺ to Fe²⁺ transformation) with a maximum absorbance of 1.195 at a concentration of 300 μg of the extract.     

Microvascular protective activity in rabbits of triterpenes from <Emphasis Type="Italic">Hylocereus undatus</Emphasis>

Two new pentacyclic triterpene taraxast-20-ene-3α-ol (1) and taraxast-12,20(30)-dien-3α-ol (2) were isolated from chloroform extract of leaves of Hylocereus undatus. These triterpenes showed protective activity against the increase of skin vascular permeability in rabbits. The protective effect, measured as the reduction in leakage of Evans blue, was of 53.5% and 70.1% for 1 and 2, respectively, after peritoneal treatment at a dose of 50 mg/kg. Comparison was made between the action of the compounds and a protective microvascular drug known as troxerutin (64.5%) at the same doses.     

Studies of the chemical constituents of the flower buds of <Emphasis Type="Italic">Magnolia kobus</Emphasis> and <Emphasis Type="Italic">M. salicifolia</Emphasis>

The constituents of the flower buds of Magnolia kobus DC. and M. salicifolia MAXIM. have been investigated. We isolated and identified six bis-tetrahydrofuran-type and three tetrahydrofuran-type lignan derivatives from M. kobus, and one bis-tetrahydrofuran-type lignan and eight phenylpropanoid-type derivatives from M. salicifolia. The structures of these compounds were elucidated on the basis of chemical and spectroscopic evidence.     

Tropane alkaloids from <Emphasis Type="Italic">Erythroxylum emarginatum</Emphasis>

A tropane alkaloid, anhydroecgonine methyl ester N-oxide (2), was isolated for the first time as a naturally occurring compound, with anhydroecgonine methyl ester (1) from the bark of Erythroxylum emarginatum. Compound 1 was also isolated from the twigs. Their structures were elucidated mainly by spectroscopic methods.     

(<Emphasis Type="Italic">Z</Emphasis>)-3-Hexenyl diglycosides from <Emphasis Type="Italic">Spermacoce laevis</Emphasis> Roxb.

A new (Z)-3-hexenyl O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside was isolated from the aerial part of Spermacoce laevis, along with 17 known compounds: (6S,9R)-roseoside, (Z)-3-hexenyl O-β-d-glucopyranoside, (Z)-3-hexenyl O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside, (Z)-3-hexenyl O-α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside, phenyethyl O-β-d-glucopyranoside, phenyethyl O-α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside, phenyethyl O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside, benzyl O-α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside, benzyl O-β-d-xylopyranosyl-(1→6)-β-d-glucopyranoside, asperuloside, 6α-hydroxyadoxoside, asperulosidic acid, kaempferol 3-O-β-d-glucopyranoside, kaempferol 3-O-rutinoside, quercetin 3-O-β-d-galactopyranoside, quercetin 3-O-α-l-rhamnopyranosyl-(1→6)-β-d-galactopyranoside, and rutin. The structure determinations were based on physical data and spectroscopic evidence.     

Two novel A-<Emphasis Type="Italic">seco</Emphasis>-rearranged lanostane triterpenoids from <Emphasis Type="Italic">Abies sachalinensis</Emphasis>

Further chemical study led to two new A-seco-rearranged lanostane triterpenoid derivatives (1–2) and one known compound Abiesanolide C (3) from the ethyl acetate (EtOAc) soluble fraction of the MeOH extract of Abies sachalinensis needles. The new compounds were identified as 3,4-seco-8-(14→13R)abeo-17,13-friedo-9β-lanosta-4(28), 7, 14, 24-tetraen-26,23-olide-23-hydroxy-3-oic acid and methyl-3,4-seco-8-(14→13R) abeo-17,13-friedo-9β-lanosta-4(28), 7, 14, 24-tetraen-26,23-olide-23-hydroxy-3-oate, respectively. Structural determination of these compounds were carried out by the spectral studies especially by the two digital (2D)-NMR and high-resolution (HR)-MS experiences.     

Anticonvulsant effect of <Emphasis Type="Italic">Sclerocarya birrea</Emphasis> (A. Rich.) Hochst. subsp. <Emphasis Type="Italic">caffra</Emphasis> (Sond.) Kokwaro (Anacardiaceae) stem-bark aqueous extract in mice

Sclerocarya birrea (A.Rich.) Hochst. subsp. caffra (Sond.) Kokwaro (family: Anacardiaceae) is traditionally used in South African folk medicine for the treatment, management and control of a variety of human ailments, including childhood convulsions and epilepsy. In the present study, we have investigated the anticonvulsant activity of the plant’s stem-bark aqueous extract (SBE) against pentylenetetrazole (PTZ)-, picrotoxin (PCT)-, and bicuculline (BCL)-induced seizures in mice. Phenobarbital and diazepam were used as reference anticonvulsant drugs for comparison. Like the reference anticonvulsant agents used, S. birrea SBE (100–800 mg/kg p.o.) significantly (P<0.05–0.001) delayed the onset of, and inhibited, PTZ-induced seizures. The plant extract (SBE, 100–800 mg/kg p.o.) also markedly inhibited PCT-induced seizures, but only weakly inhibited BCL-induced seizures. In general, the average onset of convulsion was delayed or inhibited, while the average duration of convulsion was not significantly altered (P>0.05). The plant extract also depressed the central nervous system. In conclusion, the findings of the present experimental animal study indicate that S. birrea SBE possesses anticonvulsant activity, thus lending pharmacological support to the suggested folkloric, ethnomedical uses of the plant extract in the management, control, and treatment of childhood convulsions and epilepsy in some rural communities of South Africa.     

Prenylated xanthones from <Emphasis Type="Italic">Hypericum ascyron</Emphasis>

Three new prenylated xanthones, 1,3,5-trihydroxy-6,7-[2′-(1-methylethenyl)-dihydrofurano]-xanthone (1), 1,3,5-trihydroxy-6,7-[2′-(1-hydroxy-1-methylethyl)-dihydrofurano]-xanthone (2), and 1,3,5-trihydroxy-6-O-prenyl-xanthone (3), together with eight known compounds were isolated from the leaves of Hypericum ascyron. Compound 3 has an O-prenyl moiety, and therefore represents the first reported xanthone to have an O-prenyl moiety from genus Hypericum. The structures of the isolated compounds were established based on spectroscopic data and on a comparison with values for previously identified analogues.     

Polygosumic acid,a new cadinane sesquiterpene from <Emphasis Type="Italic">Polygonum viscosum</Emphasis>, inhibits the growth of drug-resistant <Emphasis Type="Italic">Escherichia coli</Emphasis> and <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (MRSA) in vitro

Three new sesquiterpenes, 6-hydroxy-7-(1-methylethyl)-3,3a,6,7,8,8a-hexahydroazulene-1,4-dicarboxylic acid methyl ester (1, named viscozulenic acid methyl ester), 7-(1-methylethyl)-3,3a,6,7,8,8a-hexahydroazulene-1,4-dicarboxylic acid 1-methyl ester (2, named viscoazucinic acid) and 3-oxo-1-epi-sclerosporin (3, named polygosumic acid), have been isolated from the chloroform extract of the aerial parts of Polygonum viscosum by reversed-phase preparative high performance liquid chromatography (HPLC). The structures of these compounds were established conclusively by ultraviolet (UV), mass spectrometry (MS) and a series of 1D and 2D nuclear magnetic resonance (NMR) analyses. The anti-bacterial properties of 1–3 against 12 pathogenic bacterial strains have also been assessed by the rapid and robust microtitre-plate-based serial dilution method incorporating resazurin as an indicator of cell growth. Polygosumic acid was the most active among the sesquiterpenes and inhibited the growth of penicillin-resistant Escherichia coli (minimum inhibitory concentration, MIC=0.05 mg/ml) and methicillin-resistant Staphylococcus aureus (MRSA) (MIC=0.10 mg/ml).     

Diacylglycerol acyltransferase-inhibitory compounds from <Emphasis Type="Italic">Erythrina senegalensis</Emphasis>

Inhibition of acyl CoA:diacylglycerol acyltransferase (DGAT) is proposed to be a drug target for the treatment of obesity and type 2 diabetes. Bioassay-guided fractionation of the CH₂Cl₂-soluble extract of the stem bark of Erythrina senegalensis, using an in vitro DGAT enzyme assay, resulted in the isolation of eight known prenylflavonoids, 8-prenylleutone (1), auriculatin (2), erysenegalensein O (3), erysenegalensein D (4), erysenegalensein N (5), derrone (6), alpinumisoflavone (7), and 6,8-diprenylgenistein (8). Compounds 1, 2–4, 6, and 8 inhibited DGAT activity, with IC₅₀ values ranging from 1.1 ± 0.3 to 15.1 ± 1.1 μg/mL. On the basis of the data obtained, we propose isoflavonoids with isoprenyl groups as a novel class of DGAT inhibitors.     

Anti-allergic activity of an ethanol extract from <Emphasis Type="Italic">Salviae miltiorrhiza</Emphasis>

As part of an ongoing investigation aimed at the discovery of novel bioactive medicinal herbs with anti-inflammatory properties, the effects of an ethanolic extract from the parts of Salviae miltiorrhiza Bunge (ESM) were evaluated using in vitro and in vivo animal model analysis. ESM inhibited cyclooxygenase-2 (COX-2) and COX-1-dependent phases of prostaglandin D₂ (PGD₂) generation in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with IC₅₀ values of 3.96 μg/mL and 21.54 μg/mL, respectively. Furthermore, ESM inhibited leukotriene C₄ (LTC₄) production with an IC₅₀ value of 2.6 μg/mL. These results clearly demonstrated the dual COX-2 selective/5-lipoxygenase inhibitory activity that ESM possessed. ESM strongly inhibited a degranulation reaction in a dose dependent manner within a BMMC system, with an IC₅₀ value of 22.4 μg/mL. Additionally, ESM was tested in a rat passive cutaneous anaphylaxis (PCA) reaction assay by oral administration (25 to 100 mg/kg). ESM dose-dependently inhibited the PCA reaction, which was activated by anti-dinirophenyl (DNP) IgE. These results suggested that ESM might be beneficial in regulating various allergic reactions.     

<Emphasis Type="Italic">Perilla frutescens</Emphasis> var. <Emphasis Type="Italic">frutescens</Emphasis> in northern Laos

Twenty-eight samples of mericarps of Perilla frutescens var. frutescens were collected through fieldwork performed in Phongsali and Xieng Khouang provinces in northern Laos. No perilla samples were collected from Savannakhet province in the south although more than 20 sites were investigated. Perilla plants are mostly grown mixed with dry-paddy rice by slash-and-burn cultivation in Laos. The most popular local name for perilla mericarps in the area was “Ma Nga Chan”. Weight of 1,000 grains and hardness of the mericarps were measured, and all mericarps were found to be large (weight of 1,000 grains around 2 g) and soft (limit load weight under 300 g), which were preferred for culinary use in Laos. The composition of the essential oils obtained from the herbaceous plants raised from the mericarps was divided into five types, perillaketone, elemicine plus myristicine, shisofuran, piperitenon, and myristicine, and GC–MS analysis of these Laotian perilla samples showed that they were similar to those of corresponding types of known Japanese perilla strains. One of the shisofuran-type perilla contained large amounts of putative α-naginatene, which is likely to be an intermediate of the biosynthesis of naginataketone. The farmers' indifference to the oil type of the leaf seems to leave Laotian perilla as a good genetic resource for studies of the biosynthesis of oil compounds.     

Total synthesis and full NMR assignment of ourouparine,a yohimbane-type indole alkaloid isolated from <Emphasis Type="Italic">Gelsemium</Emphasis><Emphasis Type="Italic">sempervirens</Emphasis>

A yohimbane-type indole alkaloid, ourouparine, was found in Gelsemium sempervirens, and its structure was elucidated by spectroscopic analysis and total synthesis.