The genus Dillenia is comprised of about 100 species of evergreen and deciduous trees or shrubs of disjunct distribution in the seasonal tropics of Madagascar through South and South East Asia, Malaysia, North Australia, and Fiji. Species from this genus have been widely used in medicinal folklore to treat cancers, wounds, jaundice, fever, cough, diabetes mellitus, and diarrhea as well as hair tonics. The plants of the genus also produce edible fruits and are cultivated as ornamental plants. Flavonoids, triterpenoids, and miscellaneous compounds have been identified in the genus. Their extracts and pure compounds have been reported for their antimicrobial, anti-inflammatory, cytotoxic, antidiabetes, antioxidant, antidiarrheal, and antiprotozoal activities. Mucilage from their fruits is used in drug formulations.
beta-Galactosidase (EC. 3.2.1.23) from ripe carambola (Averrhoa carambola L. cv. B10) fruit was fractionated through a combination of ion exchange and gel filtration chromatography into four isoforms, viz. beta-galactosidase I, II, III and IV. This beta-galactosidases had apparent native molecular masses of 84, 77, 58 and 130 kDa, respectively. beta-Galactosidase I, the predominant isoform, was purified to electrophoretic homogeneity; analysis of the protein by SDS-PAGE revealed two subunits with molecular masses of 48 and 36 kDa. N-terminal amino acid sequence of the respective polypeptides shared high similarities albeit at different domains, with the deduced amino acid sequence of certain plant beta-galactosidases, thus, explaining the observed low similarity between the two subunits. beta-Galactosidase I was probably a heterodimer that have glycoprotein properties and a pI value of 7.2, with one of the potential glycosylation sites appeared to reside within the 48-kDa-polypeptide. The purified beta-galactosidase I was substantially active in hydrolyzing (1-->4)beta-linked spruce and a mixture of (1-->3)beta- and (1-->6)beta-linked gum arabic galactans. This isoform also had the capability to solubilize and depolymerize structurally intact pectins as well as to modify alkaline-soluble hemicelluloses, reflecting in part changes that occur during ripening.
A polyisoprenylated ketone named enervosanone has been isolated from the stem bark of Calophyllum enervosum together with three known compounds, cambogin, osajaxanthone and epicatechin. Their structures were determined by spectroscopic analysis. The antimicrobial evaluations of the isolated compounds were also reported.
A dimeric acylphenol and a potent α-glucosidase inhibitor, giganteone D (IC50 5.05μM), was isolated and characterized from the bark of Myristica cinnamomea King. The bark also yielded an acylphenol with an unprecedented skeleton for which the name cinnamomeone A (IC50 358.80μM) was proposed. Their structures were established by means of NMR and MS spectrometric analyses. The Lineweaver-Burk plot of giganteone D indicated that it was a mixed-type inhibitor. This is the first report on the α-glucosidase inhibiting potential of acylphenols.
A phytochemical investigation of the stem barks of the Malaysian Croton oblongus Burm.f. (Syn. Croton laevifolius Blume) (Euphorbiaceae) yielded seven previously undescribed ent-neo-clerodane diterpenoids, laevifins A - G and the known crovatin (3). Structures were established by a combination of spectroscopic methods including HRESIMS, NMR spectroscopy and X-ray crystallography. The absolute configuration of crovatin and laevifins A-G was established by comparison of experimental ECD and theoretical TDDFT ECD calculated spectra. This is the first report on the occurrence of the sesquiterpenoid cryptomeridiol in a Croton species. In vitro cytotoxicity assays on laevifins A, B and G showed moderate activities against the MCF-7 cancer cell line (IC50 102, 115 and 106 μM, respectively) while β-amyrin and acetyl aleuritolic acid showed good anti-inflammatory activity on the LPS-induced NF-κB translocation inhibition in RAW 264.7 cells assay with IC50 values of 23.5 and 35.4 μg/mL, respectively.
Phytochemical study of the fruits of Chisocheton erythrocarpus (Hiern) allowed the identification of eight undescribed limonoids, namely erythrocarpines O - V (1-6, 7a and 7b), along with seven known compounds. The structures of these compounds were elucidated based on spectroscopic and HRMS data, along with electronic circular dichroism to configure the absolute configuration. Erythrocarpines O and P are γ-hydroxybutenolide analogs of mexicanolide-type limonoids while erythrocarpine Q - V are phragmalin-type limonoids possessing a 1,29-oxymethylene bridge with either benzoyl or cinnamoyl moiety in their structures. Mosquito larvicidal activity revealed that crude DCM extract of C. erythrocarpus possessed a good larvicidal effect against Aedes aegypti larvae in 48 h (LC50 = 153.0 ppm). Subsequent larvicidal activity of isolated compounds indicated that erythrocarpine G (10) and 14-deoxyxyloccensin K (11) were responsible for the enhanced larvicidal effect of the extract, reporting LC50 values of 18.55 ppm and 41.16 ppm, respectively. Moreover, residual activity testing of the crude DCM extract revealed that the duration of its larvicidal effects is up to 14 days, where it maintained a 98 % larval mortality throughout the test period, under laboratory conditions.
Microalgae lipids and oils are potential candidates for renewable biodiesel. Many microalgae species accumulate a substantial amount of lipids and oils under environmental stresses. However, low growth rate under these adverse conditions account for the decrease in overall biomass productivity which directly influence the oil yield. This study was undertaken to investigate the effect of exogenously added auxin (indole-3-acetic acid; IAA) on the oil content, fatty acid compositions, and the expression of fatty acid biosynthetic genes in Chlorella vulgaris (UMT-M1). Auxin has been shown to regulate growth and metabolite production of several microalgae. Results showed that oil accumulation was highest on days after treatment (DAT)-2 with enriched levels of palmitic (C16:0) and stearic (C18:0) acids, while the linoleic (C18:2) and α-linolenic (C18:3n3) acids levels were markedly reduced by IAA. The elevated levels of saturated fatty acids (C16:0 and C18:0) were consistent with high expression of the β-ketoacyl ACP synthase I (KAS I) gene, while low expression of omega-6 fatty acid desaturase (ω-6 FAD) gene was consistent with low production of C18:2. However, the increment of stearoyl-ACP desaturase (SAD) gene expression upon IAA induction did not coincide with oleic acid (C18:1) production. The expression of omega-3 fatty acid desaturase (ω-3 FAD) gene showed a positive correlation with the synthesis of PUFA and C18:3n3.
The non-model microalga Messastrum gracile SE-MC4 is a potential species for biodiesel production. However, low biomass productivity hinders it from passing the life cycle assessment for biodiesel production. Therefore, the current study was aimed at uncovering the differences in the transcriptome profiles of the microalgae at early exponential and early stationary growth phases and dissecting the roles of specific differential expressed genes (DEGs) involved in cell division during M. gracile cultivation. The transcriptome analysis revealed that the photosynthetic integral membrane protein genes such as photosynthetic antenna protein were severely down-regulated during the stationary growth phase. In addition, the signaling pathways involving transcription, glyoxylate metabolism and carbon metabolism were also down-regulated during stationary growth phase. Current findings suggested that the coordination between photosynthetic integral membrane protein genes, signaling through transcription and carbon metabolism classified as prominent strategies during exponential growth stage. These findings can be applied in genetic improvement of M. gracile for biodiesel application.
Two undescribed sesquiterpenoids, namely dysoticans A and B, and three undescribed sesquiterpenoid dimers, namely dysoticans C-E, together with six analogs, were isolated from the stem bark of Dysoxylum parasiticum (Osbeck) Kosterm. (Meliaceae), growing in West Java, Indonesia. Their structures were elucidated based on extensive spectroscopic analysis and theoretical simulations of ECD spectra and 13C NMR shifts. Dysoticans A and B possessed undescribed cadinanes with minor modifications, while C and D featured unprecedented pseudo-sesquiterpenoid dimers through O-ether linkages of cadinanes and guaianes, respectively. Dysotican E was also characterized as the true-sesquiterpenoid dimer featuring eudesmane-germacrene hybrid framework from the Meliaceae family. Furthermore, A-C and E showed moderate activities against the human breast cancer MCF-7 and cervical cancer HeLa cell lines with IC50 values ranging from 22.15 to 45.14 μM. D selectively exhibited significant cytotoxicity against the HeLa cell line with an IC50 value of 13.00 ± 0.13 μM.
Two new venalstonine derivatives, viz., venacarpines A and B, and one new dioxokopsan derivative, kopsorinine, in addition to the kopsifolines A-F, and 11 other known alkaloids, were isolated from a Malayan Kopsia species. The structures of the new alkaloids were determined using NMR and MS analysis.
Six new alkaloids, viz., alstolactone, affinisine oxindole, lagumicine, N(4)-demethylalstonerine, N(4)-demethylalstonerinal, and 10-methoxycathafoline N(4)-oxide, in addition to 36 other known alkaloids, were obtained from the leaf extract of Alstonia angustifolia var. latifolia. The structures of the new alkaloids were determined using NMR and MS analysis.
The genus Acronychia (Rutaceae) comprise 44 species, most of which are represented by shrubs and small trees, distributed in a wide geographical area of South-Eastern Asia comprising China, India, Malaysia, Indonesia, Australia, and the islands of the western Pacific Ocean. Most of the species of the genus Acronychia have been used for centuries as natural remedies in the ethnomedical traditions of indigenous populations as anti-microbial, anti-fungal, anti-spasmodic, stomachic, anti-pyretic, and anti-haemorragic agent. Moreover fruits and aerial parts are used as food in salads and condiments, while the essential oil obtained from flowers and leaves has been employed in cosmetics production. Phytochemicals isolated from Acronychia spp. include acetophenones, quinoline and acridone alkaloids, flavonoids, cinnamic acids, lignans, coumarins, steroids, and triterpenes. The reported biological activities of the above mentioned natural compounds refer to anti-plasmodial, anti-cancer, anti-oxidant, anti-inflammatory, anti-fungal, and neuroprotective effects. The aim of this review is to examine in detail from a phytochemical and pharmacologically point of view what is reported in the current literature about the properties of phytopreparations or individual active principles obtained from plants belonging to the Acronychia genus.
Galloylated flavonol rhamnosides identified as kaempferol-3-O-(2″,3″,4″-tri-O-galloyl)-α-l-rhamnopyranoside, quercetin-3-O-(3″,4″-di-O-galloyl)-α-l-rhamnopyranoside, and quercetin-3-O-(2″,3″,4″-tri-O-galloyl)-α-l-rhamnopyranoside, together with five known galloylated and non-galloylated flavonol rhamnosides, were isolated from leaves of Calliandra tergemina (L.) Benth. Their structures were established using spectroscopic methods and their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) were evaluated by a microdilution method.
The kapurimycin A3-guanine adduct was formed by alkylation of the antitumour antibiotic with d(CGCG)2. The site of alkylation of the guanine was confirmed by comparative NMR studies with N-7-methyl-guanine in DMSO-d6.
Vanadium-dependent haloperoxidases belong to a class of vanadium enzymes that may have potential industrial and pharmaceutical applications due to their high stability. In this study, the 5'-flanking genomic sequence and complete reading frame encoding vanadium-dependent bromoperoxidase (GcVBPO1) was cloned from the red seaweed, Fracilaria changii, and the recombinant protein was biochemically characterized. The deduced amino acid sequence of GcVBPO1 is 1818 nucleotides in length, sharing 49% identity with the vanadium-dependent bromoperoxidases from Corralina officinalis and Cor. pilulifera, respectively. The amino acid residues associated with the binding site of vanadate cofactor were found to be conserved. The Km value of recombinant GcVBPO1 for Br(-) was 4.69 mM, while its Vmax was 10.61 μkat mg(-1) at pH 7. Substitution of Arg(379) with His(379) in the recombinant protein caused a lower affinity for Br(-), while substitution of Arg(379) with Phe(379) not only increased its affinity for Br(-) but also enabled the mutant enzyme to oxidize Cl(-). The mutant Arg(379)Phe was also found to have a lower affinity for I(-), as compared to the wild-type GcVBPO1 and mutant Arg(379)His. In addition, the Arg(379)Phe mutant has a slightly higher affinity for H2O2 compared to the wild-type GcVBPO1. Multiple cis-acting regulatory elements associated with light response, hormone signaling, and meristem expression were detected at the 5'-flanking genomic sequence of GcVBPO1. The transcript abundance of GcVBPO1 was relatively higher in seaweed samples treated with 50 parts per thousand (ppt) artificial seawater (ASW) compared to those treated in 10 and 30 ppt ASW, in support of its role in the abiotic stress response of seaweed.
We screened more than 60 Malaysian plants against two species of insects and found that Melicope subunifoliolata (Stapf) T.G. Hartley (Rutaceae) showed strong feeding deterrent activity against Sitophilus zeamais Motsch. (Curculionidae) and very good larvicidal activity against Aedes aegypti L. (Diptera). One anti-insect compound, meliternatin (3,5-dimethoxy-3',4',6,7-bismethylendioxyflavone) (6) and six other minor polyoxygenated flavones were isolated from M. subunifoliolata.
Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts of different Glycosmis species collected in Thailand and Malaysia. All structures were elucidated by spectroscopic methods, especially 1D and 2D NMR. Six compounds were described for the first time and two were only known so far as synthetic products. The chemotaxonomic significance of flavanoid accumulation within the genus Glycosmis is highlighted.
The bark extract of Melicope subunifoliolata (Stapf) T.G. Hartley showed competitive muscarinic receptor binding activity. Six polymethoxyflavones [melibentin (1); melisimplexin (3); 3,3',4',5,7-pentamethoxyflavone (4); meliternatin (5); 3,5,8-trimethoxy-3',4',6,7-bismethylenedioxyflavone (6); and isokanugin (7)] and one furanocoumarin [5-methoxy-8-geranyloxypsoralen (2)] were isolated from the bark extract. Compounds 2 and 6 were isolated for the first time from M. subunifoliolata. The methoxyflavones (compounds 1, 3, 4, 5, 6, and 7) show moderate inhibition in a muscarinic receptor binding assay, while the furanocoumarin (compound 2) is inactive. The potency of the methoxyflavones to inhibit [(3)H]NMS-muscarinic receptor binding is influenced by the position and number of methoxy substitution. The results suggest these compounds are probably muscarinic modulators, agonists or partial agonists/antagonists.
The plants of the enigmatic genus Rafflesia are well known for their gigantic flowers and their floral features such as pungent floral scent and vivid dark color, which mimics the food/brood sites of carrion. However, information on the pollination biology of this plant group remains limited and mostly anecdotal. In the present paper, we studied the floral volatiles of R. cantleyi Solms-Laubach and their role in pollinator attraction. To achieve these aims, the floral scent was collected in situ in the field using a dynamic headspace method followed by chemical analysis via GC-MS. The olfactory preferences of pollinators to the identified chemical compounds, were tested singly and in blends, in flight tunnel bioassays and compared with responses to headspace floral extracts. In addition, flower-visiting calliphorid flies and the local carrion fly community were sampled and identified. Five species of calliphorid flies (subfamilies of Chrysomyinae and Calliphorinae), all females, were found on the flowers, whereas nine species were found in the traps that were baited with tainted meat in the surrounding habitat. However, only flower visitors of one blow fly species, Chrysomya chani Kurahashi, were observed to carry R. cantleyi pollen after visiting male flowers. The floral volatiles emitted by male flowers in full bloom were dominated by two sulphur-containing compounds, dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS). These were accompanied by other minor compounds such as benzenoids (4), monoterpenoids (4), trace amounts of aliphatic compounds (1), and sesquiterpenes (1). In flight-tunnel bioassays, a female-specific positive response of C. chani flies to individual DMDS, DMTS, and a blend of DMDS and DMTS was evident. Our findings suggest that R. cantleyi biochemically mimics carrion and that relative ratio of oligosulfides in the floral scent play a key role in sex-biased pollinator specialization, attracting only female C. chani carrion flies to the flowers.
Eleven indole alkaloids, comprising four corynanthean, two eburnane, one aspidofractinine, one secoleuconoxine, one andranginine, and two pauciflorine type alkaloids were isolated from the stem-bark and leaf extracts of Kopsia pauciflora. Their structures were determined using NMR and MS analyses. The catharinensine type alkaloid kopsirensine B and the secoleuconoxine alkaloid arboloscine A showed moderate to weak activity in reversing MDR in vincristine-resistant KB cells. The alkaloid content was markedly different compared to that of a sample from Malaysian Borneo.