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.
In a continuation of our study of the Rutaceae, detailed chemical investigation on Micromelum minutum (Rutaceae) collected from Sepilok, Sabah, Malaysia gave four new coumarins. The structures of the coumarins have been fully characterised by spectroscopic methods as 3",4"-dihydrocapnolactone 1, 2',3'-epoxyisocapnolactone 2, 8-hydroxyisocapnolactone-2',3'-diol 3 and 8-hydroxy-3",4"-dihydrocapnolactone-2',3'-diol 4.
A new flavonoid, dihydroglychalcone-A, was isolated from the leaves extract of Glycosmis chlorosperma in addition to two known sulphur-containing amides, dambullin and gerambullin. The structure of the new compound was assigned as 2'-hydroxy-4,6'-dimethoxy-3',4'-(2",2"-dimethylpyrano)dihydrochalcone. The extract of the leaves was also found to exhibit antimicrobial and cytotoxic activities.
Leaf extracts of Melicope lunu-ankenda were chemically studied and found to contain mixtures of hydrocarbons and squalene, fatty acids and esters. A geranylated coumaric acid was isolated as the major compound. The crude dichloromethane and methanol extracts of the leaves were found to be strongly larvicidal with LC50 values below 20 microg mL(-1). This is a first isolation of p-O-geranylcoumaric acid from this plant.
A new coumarin, 8,4''-dihydroxy-3'',4''-dihydrocapnolactone-2',3'-diol (1) and two known triterpenes, 5(6)-gluten-3-one (2) and 5(6)-gluten-3alpha-ol (3) were isolated from the leaves of Micromelum minutum (Rutaceae) collected from Sepilok, Sabah, Malaysia and their structures were characterized by spectroscopic methods.
Investigation on the leaves of Melicope bonwickii (F.Muell.) T.Hartley (Rutaceae) afforded a new 7-(2'-hydroxy-3'-chloroprenyloxy)-4-methoxyfuroquinoline (1) together with the known 7-(2',3'-epoxyprenyloxy)-4-methoxyfuroquinoline (2), evellerine (3) kokusaginine (4) and an amide aurantiamide acetate (5). Compounds 1 and 2 showed significant activity against cervical cell lines (Hela).
The leaves of Melicope ptelefolia (Rutaceae) afforded a new acetophenone named 2,4,6-trihydroxy-3-geranylacetophenone. The structure of the compound was established by mass and NMR spectroscopy.
A new carbazole alkaloid, 3-carbomethoxy-2-hydroxy-7-methoxycarbazole, Clausine-TY (1), together with two known carbazole alkaloid, Clausine-H (2) and Clausine-B (3), were isolated from the ethyl acetate extract of the stem bark of the Malaysian Clausena excavata. The structures of these compounds were elucidated by spectroscopic analyses. The new carbazole alkaloid shows significant cytotoxicity against CEM-SS cell line.
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.
A preliminary study was conducted to determine the level of oxidative DNA damage, fruits and vegetables intake among 50 breast cancer patients (cases) as compared to 50 healthy women (controls) with no known medical history of breast cancer in Klang Valley. Both groups were matched for age and ethnicity. Data on socio-demographic, health status and medical history, fruits and vegetables intake, and supplements intake were obtained through an interviewbased questionnaire. Anthropometry measurements included weight, height, and waist and hip circumference were also carried out on subjects. A total of 3mL fasting venous blood was drawn to assess lymphocytes oxidative DNA damage using Alkaline Comet Assay. Results indicated that the mean intake of fruits and vegetables was lower in cases (4.09 ± 1.17 servings/d) than controls (4.77 ± 0.90 servings/d)(p < 0.05) The intake of fruits and vegetables from family groups of solanaceae, myrtaceae, caricaceae, apiaceae, brinjal, rutaceae, broccoli, orange, carrot, watermelon were 0.5 - 1 servings/week significantly higher among controls as compared to cases (p < 0.05 for all parameters). However, the intake of fruits from rosaceae family and apple was higher among controls than cases (p < 0.05). The estimated intake of ß-carotene, carotenoids, vitamin A, vitamin C (p < 0.001), a-carotene and lycopene (p < 0.05) from fruits and vegetables were higher among controls than cases. Mean DNA damage level of cases (4.55 ± 1.78 % DNA in tail, %TD; 0.35 ± 0.21 tail moment, TM) were 3.5 and 3.9 times higher than the value of controls (1.3 ± 0.70% TD; 0.09 ± 0.09 TM) (p < 0.001) and the damage increased with higher values of waist hip ratio (% TD, r = 0.396, p < 0.05; TM, r = 0.349, p < 0.05) and waist circumference (% TD, r = 0.334, p < 0.05; TM, r = 0.360, p < 0.05). There was an inverse relationship between oxidative DNA damage with intake of total fruits and vegetables, cauliflowers and water convolvulus and also consumption from rutaceae and solanaceae families. Similar trend was noted for estimated intake of vitamin A, carotenoids, vitamin C, ß-carotene and lycopene. In conclusion, the intake of fruits and vegetables of five servings/d and the consumption of specific families and types of fruits and vegetables might protect against oxidative DNA damage and further reduce breast cancer risk.
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.
Melicope ptelefolia is a medicinal herb commonly used in Malaysia to treat fever, pain, wounds, and itches. The present study was conducted to evaluate the antinociceptive activity of the Melicope ptelefolia ethanolic extract (MPEE) using animal models of nociception. The antinociceptive activity of the extract was assessed using acetic acid-induced abdominal writhing, hot-plate, and formalin-induced paw licking tests. Oral administration of MPEE produced significant dose-dependent antinociceptive effects when tested in mice and rats using acetic acid-induced abdominal constriction test and on the second phase of the formalin-induced paw licking test, respectively. It was also demonstrated that MPEE had no effect on the response latency time to the heat stimulus in the thermal model of the hot-plate test. In addition, the antinociception produced by MPEE was not blocked by naloxone. Furthermore, oral administration of MPEE did not produce any effect in motor performance of the rota-rod test and in acute toxicity study no abnormal behaviors as well as mortality were observed up to a dose level of the extract of 5 g/kg. These results indicated that MPEE at all doses investigated which did not produce any sedative and toxic effects exerted pronounce antinociceptive activity that acts peripherally in experimental animals.
Phytochemical investigations on the methanolic extract of Melicope ptelefolia Champ ex Benth. resulted in the isolation of three new compounds, identified as 3beta-stigmast-5-en-3-ol butyl tridecanedioate (melicoester) (1), (2Z, 6Z, 10Z, 14Z, 18Z, 22Z, 26E)-3', 7', 11', 15', 19', 23', 27', 31'-octamethyldotriaconta-2, 6, 10, 14, 18, 22, 26, 30-octadecanoate (melicopeprenoate) (2) and p-O-geranyl-7"-acetoxy coumaric acid (3). The compounds were isolated along with twenty-one other known compounds, lupeol (4), oleanolic acid (5), kokusaginine (6) genistein (7), p-O-geranyl coumaric acid (8), 4-stigmasten-3-one (9), 3beta-hydroxystigma-5-en-7-one (10) cis-phytyl palmitate (11), dodecane, dodecan-1-ol, ceryl alcohol, hentriacontanoic acid, eicosane, n-amyl alcohol, caprylic alcohol, octatriacontane, nonatriacontane, hexatriencontan-1-ol, methyl octacosanoate, beta-sitosterol, beta-sitosterol glucoside. Structures of all the compounds were established on the basis of MS and 1D and 2D NMR spectral data, as well as comparison with reported data.
During our phytochemical investigation of Haplophyllum villosum (Rutaceae), a perennial herb from Iran, a new 4,8-diaryl-3,7-dioxobicyclo-(3,3,0)-octane type lignan, eudesmin A (1), together with four known compounds--eudesmin (2), haplamine (3), umbelliferone (4) and scopoletin (5)--were isolated from aerial parts of the plant. The structures of the compounds were elucidated using NMR spectral analysis (¹H-NMR, ¹³C-NMR, HSQC, COSY and HMBC) as well as UV, IR and MS spectra and comparison with previously reported data.
Extraction and chromatographic separation of the extracts of dried stem barks of Glycosmis macrantha lead to isolation of two new acridone alkaloids, macranthanine and 7-hydroxynoracronycine, and a known acridone, atalaphyllidine. The structures of these alkaloids were determined by detailed spectral analysis and also by comparison with reported data.
A bioassay-guided investigation of Melicope ptelefolia Champ ex Benth (Rutaceae) resulted in the identification of an acyphloroglucinol, 2,4,6-trihydroxy-3-geranylacetophenone or tHGA, as the active principle inhibiting soybean 15-LOX. The anti-inflammatory action was also demonstrated on human leukocytes, where the compound showed prominent inhibitory activity against human PBML 5-LOX, with an IC(50) value of 0.42 μM, very close to the effect produced by the commonly used standard, NDGA. The compound concentration-dependently inhibited 5-LOX product synthesis, specifically inhibiting cysteinyl leukotriene LTC(4) with an IC(50) value of 1.80 μM, and showed no cell toxicity effects. The anti-inflammatory action does not seem to proceed via redox or metal chelating mechanism since the compound tested negative for these bioactivities. Further tests on cyclooxygenases indicated that the compound acts via a dual LOX/COX inhibitory mechanism, with greater selectivity for 5-LOX and COX-2 (IC(50) value of 0.40 μM). The molecular features that govern the 5-LOX inhibitory activity was thus explored using in silico docking experiments. The residues Ile 553 and Hie 252 were the most important residues in the interaction, each contributing significant energy values of -13.45 (electrostatic) and -5.40 kcal/mol (electrostatic and Van der Waals), respectively. The hydroxyl group of the phloroglucinol core of the compound forms a 2.56Å hydrogen bond with the side chain of the carboxylate group of Ile 553. Both Ile 553 and Hie 252 are crucial amino acid residues which chelate with the metal ion in the active site. Distorting the geometry of these ligands could be the reason for the inhibition activity shown by tHGA. The molecular simulation studies supported the bioassay results and served as a good model for understanding the way tHGA binds in the active site of human 5-LOX enzyme.
Melicope ptelefolia (MP) is one of the alternative herbal resources which have a great potential to be marketed worldwide. Because of its exploratory nature, this study used qualitative research methodology, which is natural and highly interpretive in order to gain consumer insights. This preliminary qualitative study used an in-depth personal interview approach for data collection. Informants for this study were 30 regular consumers of MP, aged from 18 years old and above. From the findings, it is reported that MP had a slightly bitter taste, crunchy young leaves, pungent, and lemon-lime aroma. In terms of its physical characteristics, it is said that MP has trifoliate, green, thick, broad leaves and has small white and greenish flowers. Respondents have varying levels of awareness and knowledge regarding MP but most of them believed that medicinal products can be produced from this herb. Respondents also stressed the importance of scientific research to properly develop MP into medicinal products and turn it into alternative treatment that has commercial values in the market.
Quorum sensing regulates bacterial virulence determinants, therefore making it an interesting target to attenuate pathogens. In this work, we screened edible, endemic plants in Malaysia for anti-quorum sensing properties. Extracts from Melicope lunu-ankenda (Gaertn.) T. G. Hartley, a Malay garden salad, inhibited response of Chromobacterium violaceum CV026 to N-hexanoylhomoserine lactone, thus interfering with violacein production; reduced bioluminescence expression of E. coli [pSB401], disrupted pyocyanin synthesis, swarming motility and expression of lecA::lux of Pseudomonas aeruginosa PAO1. Although the chemical nature of the anti-QS compounds from M. lunu-ankenda is currently unknown, this study proves that endemic Malaysian plants could serve as leads in the search for anti-quorum sensing compounds.
Excised embryonic axes from seeds of three taxa, namely, Citrus suhuiensis cv. limau madu, Citrumelo (Citrus paradisi x Poncirus trifoliate) and Fortunella polyandra, were desiccated in a laminar airflow, over silica gel, and ultra-rapidly. Desiccation sensitivity (WC50) was estimated for each taxon using the quantal response model. High desiccation tolerance (WC50 = 0.11 g water per g dry mass. g/gdw) was observed for limau madu embryonic axes desiccated in a laminar airflow and ultra-rapidly (WC50 =0.10 g/gdw). Desiccation tolerance was substantially lower (WC50 = 0.19 g/gdw) for silica gel dehydration. Similarly, high desiccation tolerance (WC50 = 0.15 g/gdw) was associated with F. polyandra embryonic axes when desiccated in a laminar airflow, while a lower desiccation tolerance (WC50 = 0.17 g/gdw) was observed with silica gel dehydration. Ultra-rapid desiccation led to the highest desiccation tolerance (WC50 = 0.14 g/gdw). The dehydration rate, however, had no influence on desiccation tolerance (WC50 ~ 0.14 g/gdw) for Citrumelo embryonic axes. After each desiccation period, embryonic axes were directly immersed in liquid nitrogen (LN) followed by rapid rewarming. Normal seedling recovery of 80 to 83% for excised embryonic axes of limau madu was observed for laminar airflow and ultra-rapid dehydration, but for silica gel dehydration, 57% recovery was obtained. Similarly, for Citrumelo, high recoveries of 100% and 97% were obtained from axes desiccated in a laminar airflow and using ultra-rapid dehydration, respectively, whereas a lower value was associated with silica gel dehydration (80%). For F. polyandra, 50% recovery was obtained both for laminar airflow and ultra-rapid dehydration, while much lower recovery (43%) was associated with silica gel dehydration. Regardless of the drying method employed, axis survival percentages following exposure to LN were commensurate with the desiccation sensitivity pattern.
The ethyl acetate and methanol bark extracts of Melicope glabra were evaluated for their antioxidant capacities by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and β-carotene bleaching/linoleic acid system. Both extracts exhibited strong inhibition against the DPPH radical (IC50 values of 24.81 and 13.01 μg ml(-1), respectively) and strong antioxidant activity in β-carotene bleaching assay. Both samples were found to have high phenolic content with values of 39 and 44 mg GAE/g as indicated by Follin-Ciocalteau's reagent. Antioxidant TLC assay-guided isolation on the methanol extract led to the isolation of a new pyranocoumarin, glabranin (1), umbelliferone (2), scopoletin (3) and sesamin (4), and their structures were determined by spectroscopy. Compounds (1-3) showed significant activities on DPPH free radical with the IC50 of 240.20, 810.02 and 413.19 μg ml(-1), respectively. However, in β-carotene bleaching assay, sesamin (4) showed higher inhibitory activity (1 mg ml(-1), 95%) than glabranin (1) (1 mg ml(-1), 74%), whilst umbelliferone (2) and scopoletin (3) were slightly pro-oxidant.