Antiviral activities of some traditional medicinal plants of Sri Lanka

Abstract:

The aim of this article is to review the antiviral activity of plants traditionally used in indigenous medicine in Sri Lanka, their therapeutic potential, chemistry, and botany. Viral infections represent an increasing threat to humans worldwide. Conventional antiviral drugs are available against respiratory viruses. Naturally occurring antiviral activity of medicinal plants was used for centuries in the country’s rich traditional medicine system consisting of Ayurveda, Siddha, Unani, and Deshiya Chikitsa. Traditional physicians cure diseases, including those that originate from viruses, through herbal medicine. To complement this, about 1430 species representing 838 genera, equivalent to 45% of the entire flowering plant community, are considered medicinal. The present article attempts to review the essence of decades of discoveries on antiviral and related properties of 21 medicinal plants, Allium sativum L., Annona muricata L., Ardisia elliptica Thunb., Azadirachta indica A. Juss., Caesalpinia pulcherrima (L.) Sw., Coriandrum sativum L., Coscinium fenestratum (Gaertn.) Colebr., Hedyotis corymbosa (L.) Lam., Hemidesmus indicus (L.) R. Br., Justicia adhatoda L., Ocimum tenuiflorum L., Phyllanthus embilica L., Phyllanthus debilis Klein ex Willd., Piper longum L., Piper nigrum L., Solanum xanthocarpum Schrad & Wendl., Terminalia bellirica (Gaertn.) Roxb., Terminalia chebula Retz., Tinospora cordifolia (Wild) Miers., Vitex negundo L., Zingiber officinale Roscoe. Among the medicinal plants commonly used in Sri Lankan traditional medicine, Justicia adhatoda showed stronger anti-influenza virus activity, inhibiting virus attachment and replication, while Terminalia chebula consisting of chebulagic and chebulinic acids, demonstrated direct antiviral activity against sexually transmitted herpes simplex virus-2 (HSV-2).

(R)-13aα-Densiindolizidine, A New Phenanthroindolizidine Alkaloid From Cryptocarya densiflora Blume (Lauraceae) and Molecular Docking Against SARS-CoV-2

Cryptocarya densiflora Blume (Lauraceae) is an evergreen tree widely distributed throughout the hills and mountain forests up to 1500 m in Malaysia and Indonesia. The plant has been reported to contain phenanthroindolizidine-type of alkaloids. In the present work, a new phenanthroindolizidine alkaloid named ( R)-13a α-densiindolizidine, was isolated from the dichloromethane (DCM) extract of the leaves. The structure of the alkaloid was established based on 1D and 2D nuclear magnetic resonance (NMR) and liquid chromatography mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) analysis. ( R)-13a α-densiindolizidine displayed binding interactions with crucial amino acid residues in the active sites ofsevere acute respiratory syndrome coronavirus 2 Mpro (SARS-CoV-2 Mpro) and RNA-dependent protease (RdRp) in silico, whilst fulfilling theabsorption, distribution, metabolism, excretion, and toxicity (ADMET) criteria and Lipinsky's rule, thus revealing its potential as a lead compound.

Recent advances in the synthesis of naturally occurring tetronic acids

During the last decades the interest towards natural products containing the tetronic acid moiety augmented significantly, due to their challenging structures and to the wide range of biological activities they display. This increasing enthusiasm has led to noteworthy advances in the development of innovative methodologies for the construction of the butenolide nucleus. This review provides an overview of the progress in the synthesis of tetronic acid as a structural key motif of natural compounds, covering the last 15 years. Herein, the most representative synthetic pathways towards structurally diverse natural tetronic acids are grouped according to the strategy followed. The first part describes the functionalization of a preformed tetronic acid core by intermolecular reactions (cross-coupling reactions, nucleophilic substitution, multicomponent reactions) whereas the second part deals with intramolecular approaches (Dieckmann, cycloaddition or ring expansion reactions) to construct the heterocyclic core. This rational subcategorization allowed us to make some considerations about the best approaches for the synthesis of specific substrates, including modern intriguing methodologies such as microwave irradiation, solid phase anchoring, bio-transformations and continuous flow processes.

The Anti-Inflammatory and Antimicrobial Potential of Selected Ethnomedicinal Plants from Sri Lanka

Traditional folk medicine in Sri Lanka is mostly based on plants and plant-derived products, however, many of these medicinal plant species are scientifically unexplored. Here, we evaluated the anti-inflammatory and antimicrobial potency of 28 different extracts prepared from seven popular medicinal plant species employed in Sri Lanka. The extracts were subjected to cell-based and cell-free assays of 5-lipoxygenase (5-LO), microsomal prostaglandin E₂ synthase (mPGES)-1, and nitric oxide (NO) scavenging activity. Moreover, antibacterial and disinfectant activities were assessed. Characterization of secondary metabolites was achieved by gas chromatography coupled to mass spectrometric (GC-MS) analysis. n-Hexane- and dichloromethane-based extracts of Garcinia cambogia efficiently suppressed 5-LO activity in human neutrophils (IC₅₀ = 0.92 and 1.39 µg/mL), and potently inhibited isolated human 5-LO (IC₅₀ = 0.15 and 0.16 µg/mL) and mPGES-1 (IC₅₀ = 0.29 and 0.49 µg/mL). Lipophilic extracts of Pothos scandens displayed potent inhibition of mPGES-1 only. A methanolic extract of Ophiorrhiza mungos caused significant NO scavenging activity. The lipophilic extracts of G. cambogia exhibited prominent antibacterial and disinfectant activities, and GC-MS analysis revealed the presence of fatty acids, sesquiterpenes and other types of secondary metabolites. Together, our results suggest the prospective utilization of G.cambogia as disinfective agent with potent anti-inflammatory properties.

Secondary Metabolites Produced by an Endophytic Fungus Pestalotiopsis microspora

An endophytic fungus Pestalotiopsis microspora isolated from the fruits of Manilkara zapota was cultured in potato dextrose broth media. Chromatographic separation of the EtOAc extract of the broth and mycelium led to the isolation of a new azaphilonoid named pitholide E (1), in addition to previously identified pitholide B (2), pitholide D (3), pestalotin (LL-P880α) (4), PC-2 (5), LL-P880β (6), tyrosol (7) and 4-oxo-4H-pyran-3-acetic acid (8). An endophytic fungus P. microspora from M. zapota and the isolation of compounds 1-5, 7 and 8 from P. microspora are reported here for the first time.

Isocoumarins and Dihydroisocoumarins From the Endophytic Fungus Biscogniauxia capnodes Isolated From the Fruits of Averrhoa carambola

An endophytic fungus Biscogniauxia capnodes was isolated from a popular edible fruit Averrhoa carambola. The fungus was fermented in potato dextrose broth for 3 weeks, and then the culture broth and mycelium were extracted with ethyl acetate. Chromatographic separation of this extract furnished 2 isocoumarins, reticulol (1) and 6- O-methyl-reticulol (2), and 2 dihydroisocoumarins, 5-methylmellein (3) and 7-hydroxy-5-methylmellein (4). Compound 1 showed moderate antioxidant activity against 2,2′-diphenyl-1-picrylhydrazyl radicals (IC50 value, 58 μg/mL). This is the first report of the isolation of B. capnodes as an endophyte, as well as the compounds 1 to 4 from B. capnodes.

Heat stability of the in vitro inhibitory effect of spices on lipase, amylase, and glucosidase enzymes

This study investigated the effect of boiling on the inhibitory action of spices on digestive enzymes. Unboiled extracts of Trigonella foenum-graecum (seed) (25.42%), Myristica fragrans (seed) (22.70%), and Cuminum cyminum (seed) (19.17%) showed significantly (p < 0.05) a higher lipase inhibitory activity than their respective boiled extracts (20.23%, 15.74%, and 12.57%). Unboiled extracts of Cinnamomum zeylanicum (stem bark) (-16.98%) and Foeniculum officinale (seed) (-16.05%) showed an activation of lipase enzyme, and boiling significantly (p < 0.05) changed the activity into lipase inhibition as 8.47% and 9.54%, respectively. Unboiled extracts of Coriandrm sativum (seed), C. cyminum, and Elettaria cardamomum (seed) showed an activation of amylase enzyme, and boiling these extracts significantly reduced the enzyme activation. The other unboiled extracts showed a higher amylase inhibition than the boiled extracts, whereas the boiled extracts of C.longa (rhizome) and Syzygium aromaticum (flower) exhibited significantly (p < 0.05) lower values. Unboiled extracts of C. zeylanicum, M. fragrans, and S. aromaticum showed an insignificantly higher glucosidase inhibitory activity than the boiled extracts. Inhibition of digestive enzymes by nutritional intervention is one avenue to be considered in treating diet-induced obesity and in the management of postprandial hyperglycemia. Spices, used as food additives, could be a potential source of digestive enzyme inhibitors. The current study revealed that unboiled extracts of T. foenum-graecum (seed), C. cyminum (seed), and M. fragrans (seed) are more effective than the boiled extracts as an antiobesity therapy. Moreover, it endorses the use of infusion of T. foenum-graecum seeds as an antiobesity therapy.

Lipophilic extracts of Leucas zeylanica, a multi-purpose medicinal plant in the tropics, inhibit key enzymes involved in inflammation and gout

ETHNOPHARMACOLOGICAL RELEVANCE

Leucas zeylanica (L.) W.T. Aiton is a popular, multi-purpose medicinal plant in Sri Lanka but the pharmacological potential and the chemical profile have not been systematically investigated to understand and rationalize the reported ethnobotanical significance.

AIM OF THE STUDY

The present study was undertaken to scientifically validate the traditional usage of this plant for the treatment of inflammatory conditions, gout and microbial infections. Inhibition of 5-lipoxygenase (5-LO), microsomal prostaglandin E₂ synthase (mPGES)-1 and xanthine oxidase (XO) by different extracts of L. zeylanica was investigated to determine the anti-inflammatory and anti-gout activity, respectively. The antibacterial and antifungal activities were also studied and the relevant constituents in the bioactive extracts were tentatively identified.

MATERIALS AND METHODS

Cell-free and/or cell-based assays were employed in order to investigate the effects of the extracts against the activity of human 5-LO, mPGES-1 and XO as well as to assess antioxidant properties. The antibacterial activity of the extracts was determined by the broth micro-dilution method against Gram positive and Gram negative bacteria including methicillin-resistant Staphylococcus aureus while the agar dilution method was employed to determine the anti-Candida activity. Gas chromatography coupled to mass spectrometric (GC-MS) analysis enabled the characterization of secondary metabolites in the extracts.

RESULTS

The dichloromethane extract of L. zeylanica efficiently inhibited 5-LO activity in stimulated human neutrophils (IC₅₀ = 5.5 µg/mL) and isolated human 5-LO and mPGES-1 (IC₅₀ = 2.2 and 0.4 µg/mL). Potent inhibition of XO was observed by the same extract (IC₅₀ = 47.5 μg/mL), which is the first report of XO-inhibitory activity of a Sri Lankan medicinal plant. Interestingly, significant radical scavenging activity was not observed by this extract. Only the n-hexane extract exhibited antibacterial activity against Staphylococcus aureus and Staphylococcus saprophyticus with a MIC of 250 µg/mL while the anti-Candida activity was moderate. GC-MS analysis revealed the presence of phytosterols, fatty acids, sesquiterpenes, diterpenes and several other types of secondary metabolites.

CONCLUSIONS

Potent inhibition of 5-LO, mPGES-1 and XO rationalizes the ethnopharmacological use of L. zeylanica as anti-inflammatory and anti-gout remedy. Interestingly, the antimicrobial activities were not prominent, despite its wide utility as an antimicrobial medication.

Naphthoquinone Metabolites Produced by Monacrosporium ambrosium, the Ectosymbiotic Fungus of Tea Shot-Hole Borer, Euwallacea fornicatus, in Stems of Tea, Camellia sinensis

The tea shot-hole borer beetle (TSHB, Euwallacea fornicatus) causes serious damage in plantations of tea, Camellia sinensis var. assamica, in Sri Lanka and South India. TSHB is found in symbiotic association with the ambrosia fungus, Monacrosporium ambrosium (syn. Fusarium ambrosium), in galleries located within stems of tea bushes. M. ambrosium is known to be the sole food source of TSHB. Six naphthoquinones produced during spore germination in a laboratory culture broth of M. ambrosium were isolated and identified as dihydroanhydrojavanicin, anhydrojavanicin, javanicin, 5,8-dihydroxy-2-methyl-3-(2-oxopropyl)naphthalene-1,4-dione, anhydrofusarubin and solaniol. Chloroform extracts of tea stems with red-colored galleries occupied by TSHB contained UV active compounds similar to the above naphthoquinones. Laboratory assays demonstrated that the combined ethyl acetate extracts of the fungal culture broth and mycelium inhibited the growth of endophytic fungi Pestalotiopsis camelliae and Phoma multirostrata, which were also isolated from tea stems. Thus, pigmented naphthoquinones secreted by M. ambrosium during spore germination may prevent other fungi from invading TSHB galleries in tea stems. The antifungal nature of the naphthoquinone extract suggests that it protects the habitat of TSHB. We propose that the TSHB fungal ectosymbiont M. ambrosium provides not only the food and sterol skeleton necessary for the development of the beetle during its larval stages, but also serves as a producer of fungal inhibitors that help to preserve the purity of the fungal garden of TSHB.

Chemical investigation of metabolites produced by an endophytic fungi Phialemonium curvatum from the leaves of Passiflora edulis

Phialemonium curvatum, an endophytic fungus isolated from the leaves of Passiflora edulis was cultured in potato dextrose broth (PDB) media and chromatographic separation of the EtOAc extract of the broth and mycelium led to the isolation of 4-hydroxybenzoic acid (1), 3-indole acetic acid (2), solaniol (3), uracil (4), uridine (5) and glycerol (6). Compound 2 showed a weak antifungal activity against Cladosporium cladosporioides. This is the first report of the isolation of the endophytic fungus P. curvatum from P. edulis and complete ¹³CNMR assignments of 3.

Bioassay-guided fractionation and identification of α-amylase inhibitors from Syzygium cumini leaves

CONTEXT

Pancreatic α-amylase and α-glucosidase inhibitors serve as important strategies in the management of blood glucose. Even though Syzygium cumini (L.) Skeels (Myrtaceae) (SC) is used extensively to treat diabetes; scientific evidence on antidiabetic effects of SC leaves is scarce.

OBJECTIVE

SC leaf extract was investigated for α-amylase inhibitory effect and continued with isolation and identification of α-amylase inhibitors.

MATERIALS AND METHODS

Bioassay-guided fractionation was conducted using in vitro α-amylase inhibitory assay (with 20-1000 μg/mL test material) to isolate the inhibitory compounds from ethyl acetate extract of SC leaves. Structures of the isolated inhibitory compounds were elucidated using 1H NMR and 13C NMR spectroscopic analysis and direct TLC and HPLC comparison with authentic samples. Study period was from October 2013 to October 2015.

RESULTS

An active fraction obtained with chromatographic separation of the extract inhibited porcine pancreatic α-amylase with an IC50 of 39.9 μg/mL. Furthermore, it showed a strong inhibition on α-glucosidase with an IC50 of 28.2 μg/mL. The active fraction was determined to be a 3:1 mixture of ursolic acid and oleanolic acid. Pure ursolic acid and oleanolic acid showed IC50 values of 6.7 and 57.4 μg/mL, respectively, against α-amylase and 3.1 and 44.1 μg/mL respectively, against α-glucosidase.

DISCUSSION AND CONCLUSIONS

The present study revealed strong α-amylase and α-glucosidase inhibitory effects of ursolic acid and oleanolic acid isolated from SC leaves for the first time validating the use of SC leaves in antidiabetic therapy.

Factors influencing diurnal variation in height among adults

This study evaluates height loss during the day in light of variables assessable through participant self-report. Participants were 19 female and 15 male staff and students who met with us twice with a mean interval between measurement sessions of 6.96h (SD=0.86). Hypotheses were evaluated using two-stage least squares regression analysis (SYSTAT 10). Males and females lost similar amounts of height between sessions (male,x¯=6.9mm;female,x¯=7.4mm). Among factors considered to impact overall height loss, sleep duration (Adj. R²=0.181, p=0.022) and height (Adj. R²=0.121, p=0.048) were useful in univariate analyses, though they were not significant in any models that included variables other than sex. Judging from log-transformed BMI variation, heavier males and females lost more height (F_{(2, 31)}=4.59, Adj. R²=0.179, p=0.018). Among factors anticipated to reduce height loss by acting prior to morning measurements, only time spent walking was significantly associated (β=2.6±0.8mm, t=3.16, p=0.004) when included as a predictor along with sex (p=0.17) and log-BMI (p=0.003). This model explained about 38% of height loss variance. None of the factors considered as potentially acting between measurement sessions showed statistically significant influences when included in the model just described, though predictor coefficients were in the anticipated direction. Results suggest that self-reported activities may be an important supplement to anthropometric studies, both for planning and later evaluation, particularly in large studies.

Talarofuranone, a New Talaroconvolutin Analog from the Endophytic Fungus Talaromyces purpurogenus from Pouteria campechiana Seeds

An endophytic fungus Talaronyces pinpurogenus was isolated from the seeds of the popular edible fruit Pouteria campechiana. The fungus was fermented in potato dextrose agar and the fungal media were extracted with EtOAc. Chromatographic separation of the EtOAc extracts over silica gel, Sephadex LH-20 and preparative thin layer chromatography furnished a furanone analogue of talaroconvolutin A, named talarofuranone (1), along with talaroconvolutin A (2), 4-hydroxyactophenone, tyrosol and ergosterol. The structure of 1 was determined by comparing the NMR data with that of 2 and by HRFABMS.

Talarofuranone, a New Talaroconvolutin Analog from the Endophytic Fungus Talaromyces purpurogenus from Pouteria campechiana Seeds

An endophytic fungus Talaromyces purpurogenus was isolated from the seeds of the popular edible fruit Pouteria campechiana. The fungus was fermented in potato dextrose agar and the fungal media were extracted with EtOAc. Chromatographic separation of the EtOAc extracts over silica gel, Sephadex LH-20 and preparative thin layer chromatography furnished a furanone analogue of talaroconvolutin A, named talarofuranone (1), along with talaroconvolutin A (2), 4-hydroxyacetophenone, tyrosol and ergosterol. The structure of 1 was determined by comparing the NMR data with that of 2 and by HRFABMS.

Photoprotective potential in some medicinal plants used to treat skin diseases in Sri Lanka

BACKGROUND

The constant exposure to solar ultraviolet radiation (UV) has a variety of harmful effects on human health. Although synthetic sunscreen products have been introduced as a preventive/therapeutic strategy, with the realization of their adverse side effects, the recent trend is to search for human friendly alternative formulations especially of plant origin. Therefore, the present study focuses on evaluation of photoprotective activity of aqueous extracts (1 mg/ml) of eleven medicinal plants in Sri Lanka that have been widely employed in traditional medicine as treatment options for various skin diseases and to improve the complexion.

METHODS

For the determination of UV filtering potential of the extracts, UV absorption was measured and the sun protection factor (SPF) was calculated according the Mansur equation. The antioxidant activity was evaluated by DPPH and ABTS assays.

RESULTS

Among the extracts, Atalantia ceylanica, Hibiscus furcatus, Leucas zeylanica, Mollugo cerviana, Olax zeylanica and Ophiorrhiza mungos have displayed SPF value ≥ 25, which are even higher than two commercial photoprotective creams used as reference compounds. L. zeylanica and O. mungos have displayed a high UV absorbance in 260-350 nm range indicating their potential of being broad spectrum sunscreens. In addition, the extract of O. mungos was found to be photostable, without any significant reduction in the SPF after exposure to direct solar radiation for 21 days. DPPH assay and the ABTS assay revealed that the extracts possess high antioxidant activity.

CONCLUSION

The results of the present study suggest that the presence of secondary metabolites with antioxidant property could be responsible for the high UV absorbance. Our findings would offer an exciting avenue for further research towards the development of herbal cosmetics.

Antioxidant property and [Formula: see text]-glucosidase, [Formula: see text]-amylase and lipase inhibiting activities of Flacourtia inermis fruits: characterization of malic acid as an inhibitor of the enzymes

Flacourtia inermis Roxb. (Flacourtiaceae), is a moderate sized tree cultivated in Sri Lanka for its fruits known as Lovi. The current study was undertaken to study the biological activity of extracts of the fruits in an attempt to increase the value of the under exploited fruit crops. Fruits of F. inermis were found to be rich in phenolics and anthocyanins. Polyphenol content of the fruits was determined to be 1.28 g gallic acid equivalents per 100 g of fresh fruit and anthocyanin content was estimated as 108 mg cyanidin-3-glucoside equivalents per 100 g of fresh fruits. The EtOAc extract showed moderate antioxidant activity in the DPPH radical scavenging assay with IC50 value of 66.2 ppm. The EtOAc and MeOH extracts of the fruits also exhibited inhibitory activities toward α-glucosidase, α-amylase and lipase enzymes with IC50values ranging from 549 to 710 ppm, 1021 to 1949 ppm and 1290 to 2096 ppm, respectively. The active principle for the enzyme inhibition was isolated through activity-guided fractionation and was characterized as (S)-malic acid. The results of this study indicate that F. inermis fruits have the potential to be used in health foods and in nutritional supplements.

A 3-Vinyl Cephem Derivative, a Useful Intermediate in the Synthesis of Cepham Antibiotics, from Aspergillus awamori Associated with Banana Fruit

Aspergillus awamori was isolated from a diseased banana fruit, Musa acuminata cv. Ambul. The fungus was fermented in potato dextrose broth and on potato dextrose agar media and the fungal media were extracted with EtOAc. Chromatographic separation of the EtOAc extracts furnished 4-methoxybenzyl 7-phenylacetamido-3-vinyl-3-cephem-4-carboxylate (1), along with three naphtho-γ-pyrones, flavasperone (2), foncesinone A (3) and aurasperone A (4), and three alkaloids, aspernigrin A (5), pestalamide C (6) and nigragillin (7). Compound 1, a known key intermediate in the chemical synthesis of cepham antibiotics, was isolated from a natural source for the first time. Compound 1 is the first 3-vinyl cephem derivative of microbial origin.

Endophytic Fungus Nigrospora oryzae from a Medicinal plant Coccinia grandis, a High Yielding New Source of Phenazine-1-carboxamide

Nigrospora oryzae was isolated as an endophytic fungus from the leaves of Coccinia grandis, a popular medicinal plant used to control diabetes. Fermentation of the fungus in potato dextrose broth and chromatographic purification of the ethyl acetate extracts of the broth and mycelium yielded two phenazine secondary metabolites, which were identified as phenazine-1-carboxylic acid (1) and phenazine-1-carboxamide (2) by comparing their spectral data with those reported in the literature. Compound 2, isolated in high yield (1 g/4 L medium), showed strong antifungal activity against the plant pathogen Cladosporium cladosporioides. This is the first report of the isolation of N. oryzae as an endophytic fungus of C. grandis. These phenazines have never been isolated from any fungal source. Antifungal activity of 2 against C. cladosporioides is reported for the first time.

A 3-Vinyl Cephem Derivative, a Useful Intermediate in the Synthesis of Cepham Antibiotics, from Aspergillus awamori Associated with Banana Fruit

Aspergillus awamori was isolated from a diseased banana fruit, Musa acuminata cv. Ambul. The fungus was fermented in potato dextrose broth and on potato dextrose agar media and the fungal media were extracted with EtOAc. Chromatographic separation of the EtOAc extracts furnished 4-methoxybenzyl 7-phenylacetamido-3-vinyl-3-cephem-4-carboxylate (1), along with three naphtho-γ-pyrones, flavasperone (2), foncesinone A (3) and aurasperone A (4), and three alkaloids, aspernigrin A (5), pestalamide C (6) and nigragillin (7). Compound 1, a known key intermediate in the chemical synthesis of cepham antibiotics, was isolated from a natural source for the first time. Compound 1 is the first 3-vinyl cephem derivative of microbial origin.

Two phytotoxic azaphilone derivatives from Chaetomium globosum, a fungal endophyte isolated from Amaranthus viridis leaves

A fungal endophyte isolated from the leaves of the allelopathic plant Amaranthus viridis of the family Amaranthaceae was identified as Chaetomium globosum through molecular means using internal transcribed spacer (ITS) region of rDNA gene. This is the first report of the isolation of C. globosum from Amaranthaceae. Chromatographic separation of the EtOAc extract of the fungal fermentation in potato dextrose broth yielded two known chlorine-containing azaphilone derivatives, chaetomugilin D (1) and chaetomugilin J (2). Compounds 1 and 2 were found to show phytotoxic activity in the lettuce (Lactuca sativa) seed germination bioassay. The IC₅₀ values of 1 and 2 for root growth inhibition were 24.2 and 22.6 ppm, respectively, while IC₅₀ values for shoot growth inhibition were 27.8 and 21.9 ppm, respectively. Phytotoxic activities of the chaetomugilin group of compounds have been reported for the first time, although their antifungal, antimicrobial and cytotoxic activities are known.

Identification and characterization of proanthocyanidins of 16 members of the Rhododendron genus (Ericaceae) by tandem LC-MS

The proanthocyanidins of the leaves of 16 taxa of the Rhododendron genus (Ericaceae) [Rhododendron 'Catawbiense Grandiflorum', Rhododendron 'Cunningham's White', Rhododendron smirnowii Trautv., Rhododendron calophytum Franch., Rhododendron dichroanthum ssp. scyphocalyx (Balf. f. & Forrest ) Cowan, Rhododendron micranthum Turcz., Rhododendron praevernum Hutch., Rhododendron ungernii Trautv., Rhododendron kaempferi Planch., Rhododendron degronianum ssp. heptamerum var. hondoense (Nakai ) H. Hara, Rhododendron fortunei Lindl., Rhododendron ponticum L., Rhododendron galactinum Balf. f. ex Tagg., Rhododendron oreotrephes W. W. Sm., Rhododendron brachycarpum ssp. brachycarpum D. Don ex G. Don, and Rhododendron insigne Hemsl. & E. H. Wilson ] were investigated qualitatively by liquid chromatography-mass spectrometry in series. Twenty-nine dimeric proanthocyanidins based on (epi)catechin and (epi)gallocatechin were detected and characterized on the basis of their unique fragmentation pattern in the negative ion mode tandem mass spectrometry spectra. All of them were extracted for the first time from these sources, and ten of them were not reported previously in nature. The position of the galloyl residue was assigned on the basis of the retro-Diels-Alder fragmentation and the dehydrated retro-Diels-Alder fragmentation; it resulted from the loss of gallic acid as a neutral loss in the negative ion mode. Furthermore, four caffeoylquinic acids, six p-coumaroylquinic acids, epigallocatechin, gallocatechin, catechin, epicatechin, epigallocatechin gallate, catechin gallate, epicatechin gallate, gallocatechin gallate, two quercetin-O-hexosides, quercetin-O-galloyl-hexoside, quercetin-O-pentoside, quercetin-O-rhamnoside, quercetin-O-pentoside-O-hexoside, quercetin-O-rhamnoside-O-hexoside, quercetin-O-feruloyl-hexoside, quercetin-O-(p-hydroxy)benzoyl-hexoside, taxifolin-O-pentoside, myricetin-O-rhamnoside, two myricetin-O-pentosides, three myricetin-O-hexosides, and two myricetin-O-galloyl-hexosides were detected and shown to possess characteristic tandem mass spectrometry spectra and were tentatively assigned on the basis of their retention time.

Antioxidant flavonol glycosides from Elaeocarpus serratus and Filicium decipiens

Chemical investigation of the leaves of Elaeocarpus serratus yielded myricitrin (1), mearnsetin 3-O-β-D-glucopyranoside (2), mearnsitrin (3), tamarixetin 3-O-α-L-rhamnopyranoside (4) and the fruits of Filicium decipiens yielded three flavonol glycosides, kaempferol 3-O-rutinoside (5), kaempferol 3-O-robinobioside (6) and trifolin (7). Compound 1 showed strong antioxidant activity against DPPH.

Synthesis and antifungal activity of a series of N-substituted [2-(2,4-dichlorophenyl)-3-(1,2,4-triazol-1-yl)]propylamines

A series of N-mono- or N, N-disubstituted [2-(2,4-dichlorophenyl-3-(1,2,4-triazol-1-yl)]propylamines and N-[2-(2,4-dichlorophenyl-3-(1,2,4-triazol-1-yl)propyl]amides were synthesized and tested for their fungicidal activity in vitro and in vivo against a group of plant pathogenic fungi. Some compounds exhibited a fairly good in vitro activity. The replacement of the ether group of tetraconazole with a secondary or tertiary amino group leads to compounds that maintain the antifungal activity on several phytopathogenic fungi, provided that the substituents are not too bulky or lipophilic. The allyl, propargyl, and cyclopropyl groups appear particularly suitable. Although these compounds have some structural similarities with terbinafine and naftifine, which act as squalene epoxidase inhibitors, they maintain the usual mechanism of action of the other triazoles.

Geranylated phenolic constituents from the fruits of Artocarpus nobilis

Chemical investigation of the combined dichloromethane and ethyl acetate extracts of the fruits of Artocarpus nobilis, furnished four new geranylated phenolic constituents, 2,4,4'-trihydroxy-3-[(2E)-5-methoxy-3,7-dimethylocta-2,6-dienyl]chalcone (4), 1-(3,4-dihydro-3,5-dihydroxy-2-methyl-2-(3-methyl-2-butenyl)-2H-1-benzopyran-6-yl-3-(4-hydroxyphenyl)-2(E)-propen-1-one (5), 8-geranyl-3',4',7-trihydroxyflavone (8), 3'-geranyl-4',5,7-trihydroxyflavanone (9), together with known related compounds, xanthoangelol (1), xanthoangelol B (2), 3-geranyl-2,3',4,4'-tetrahydroxychalcone (3), lespeol (6), 8-geranyl-4',7-dihydroxyflavanone (7), and isonymphaeol-B (10). Compounds 3, 8 and 10 showed strong antioxidant activity against DPPH radical by spectrophotometric method.

N-Methyl-4-hydroxy-2-pyridinone analogues from Fusarium oxysporum

Three new N-methyl-4-hydroxy-2-pyridinone analogues, 6-epi-oxysporidinone (3), the dimethyl ketal of oxysporidinone (4), and N-demethylsambutoxin (5), along with the known compounds (-)-oxysporidinone (1), (-)-sambutoxin (2), wortmannin (6), enniatin A (7), enniatin A1 (8), and enniatin B1 (9) were isolated from Fusarium oxysporum (N17B) by bioassay-guided fractionation. Compounds 1 and 3 showed selective fungistatic activity against Aspergillus fumigatus, and wortmannin had selective potent activity against Candida albicans. Moderate activity was observed with the enniatins 7-9 against C. albicans, Cryptococcus neoformans, and Mycobacterium intracellulare. Compounds 1-5 had no activity against the agriculturally important fungi Fusarium verticillioides (syn. F. moniliforme) and Aspergillus flavus.

Geranyl chalcone derivatives with antifungal and radical scavenging properties from the leaves of Artocarpus nobilis

Antifungal activity guided fractionation of the n-butanol extract from the methanol extract of the leaves of Artocarpus nobilis furnished 2',4',4-trihydroxy-3'-geranylchalcone (1), 2 ',4',4-trihydroxy-3'-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]chalcone (2), 2',4',4-trihydroxy-3'-[2-hydroxy-7-methyl-3-methylene-6-octaenyl]chalcone (3), 2',3,4,4'-tetrahydroxy-3'-geranylchalcone (4), 2',3,4,4'-tetrahydroxy-3'-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]chalcone (5). The chalcones 3 and 5 are new natural products whereas 1 and 2 are reported first time from the family Moraceae. All these compounds showed good fungicidal activity against Cladosporium cladosporioides and high radical scavenging activity towards the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC bio-autography method.

A new 3,4-seco-lupane derivative from Lasianthus gardneri

A new seco-ring A lupane triterpene derivative (1), along with lupenone, lupeol, beta-sitosterol, ursolic acid, and stigmasterol 3-O-beta-d-glucoside, were isolated from a methanol extract of mature stems of Lasianthus gardneri, a shrub from the family Rubiaceae growing in Sri Lanka. The structure and stereochemistry of the new compound were determined using a combination of (13)C and (1)H homo- and heteronuclear 2D NMR experiments and from mass spectral data. The structure of 1 was confirmed by partial synthesis from lupeol.

A new ecdysteroid, 2-deoxy-5beta,20-dihydroxyecdysone from the fruits of Diploclisia glaucescens

Chemical investigation of ethyl acetate extract of the fruits of Diploclisia glaucescens of the family Menispermaceae furnished a new ecdysteroid 2-deoxy-5beta,20-dihydroxyecdysone, together with 20-hydroxyecdysone, 3-deoxy-1beta,20-dihydroxyecdysone, 2-deoxy-20-hydroxyecdysone, 24-ethyl-20-hydroxyecdysone (makisterone C). Latter two ecdysteroids are reported first time from the family Menispermaceae.

Bidesmosidic saponins from the fruits of Diploclisia glaucescens

Chemical investigation of methanol extract of the fruits of Diploclisia glaucescens (Menispermaceae) furnished two new bidesmosidic saponins 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl]phytolaccagenic acid 28-O-beta-D-glucopyranosyl ester, 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]phytolaccagenic acid 28-O-beta-D-glucopyranosyl ester, together with known 3-O-beta-D-glucopyranosylphytolaccagenic acid 28-O-beta-D-glucopyranosyl ester and 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]serjanic acid 28-O-beta-D-glucopyranosyl ester. The last saponin is reported for the first time from the family Menispermaceae.

Antifungal constituents of the stem bark of Bridelia retusa

Antifungal activity guided fractionation of solvent extracts of the stem bark of Bridelia retusa of the family Euphorbiaceae against Cladosporium cladosporioides, furnished new bisabolane sesquiterpenes, (E)-4-(1,5-dimethyl-3-oxo-1-hexenyl)benzoic acid, (E)-4-(1,5-dimethyl-3-oxo-1,4-hexadienyl) benzoic acid, (R)-4-(1,5-dimethyl-3-oxo-4-hexenyl)benzoic acid and (-)-isochaminic acid, together with the known (R)-4-(1,5-dimethyl-3-oxohexyl)benzoic acid (ar-todomatuic acid), 5-allyl-1,2,3-trimethoxybenzene (elemicin), (+)-sesamin and 4-isopropylbenzoic acid (cumic acid). All these compounds showed fungicidal activity on TLC bioautography method at very low concentrations except elemicin.

3-Deoxy-1beta,20-dihydroxyecdysone from the leaves of Diploclisia glaucescens

Chemical investigation of methanol extract of the leaves of Diploclisia glaucescens of the family Menispermaceae furnished a new ecdysteroid, 3-deoxy-1beta,20-dihydroxyecdysone. The structure of the new ecdysteroid was established on detailed analysis of spectral data. The 3-deoxy ecdysteroid showed 40% potency of 20-hydroxyecdysone in the spiracle index assay using the fourth instar larvae of the silkworm Bombyx mori.

Observation of predicted resonance structure in the H+D2 --> HD(v(') = 0, j(') = 7) + D reaction at a collision energy of 0.94 eV

We present experimental verification of predicted resonance structure in the energy dependence of the H+D2 reaction. Specifically we predict and observe a broad resonance in the H+D2-->HD(v(') = 0,j(') = 7)+D reaction at a collision energy of 0. 94 eV. This resonance structure is roughly Gaussian with a full width at half maximum of 0.1 eV. These results represent the first experimentally observed resonance structure in the fundamental H+H2 reaction system.

Hederagenin glycosides from Pometia eximia

Seven new saponins, all glycosides of hederagenin (3 beta,23- dihydroxyolean-12-en-28-oic acid), were isolated from the stem of Pometia eximia along with hederagenin and two known saponins. Their structures were established as 28-O-beta-D-apiosyl(1-->2)-beta-D-glucopyranosyl-, 3-O-alpha-L- arabinofuranosyl(1-->3)[alpha-L-rhamnopyranosyl (1-->2)]-beta-D- xylopyranosyl-, 3-O-beta-D-apiosyl(1-->3)[alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-, 3-O-alpha-L-arabinofuranosyl(1-->3)[alpha-L-rhamnopyranosyl- (1-->2)]-beta-L-arabinopyranosyl-, 3-O-beta-D-xylopyranosyl(1-->3)[alpha-L- rhamnopyranosyl(1-->2)]-alpha-L-arabinopyranosyl-, 3-O-beta-D-xylopyranosyl-(1-->3)[alpha-L-rhamnopyranosyl(1-->2)]-beta-D- glucopyranosyl-, 3-O-beta-D-galactopyranosyl(1-->3)[alpha-L-rhamnopyranosyl(1-->2)]-beta- D- glucopyranosyl-hederagenins.