Records of Natural Products Articles

The occurrence of diterpenoids from roots and aerial parts of the species of the genus Stachys (Lamiaceae, Labiatae) is reviewed. The presence of these diterpenoids in other taxa and their biological properties have been also reviewed.

One triterpenic acid (ursolic acid), one phenolic acid (rosmarinic acid), and four flavonoids (luteolin, luteolin 7-O-(6”-feruloyl)- b -glucopyranoside, luteolin 5-O- b -glucopyranoside, and luteolin 7-O- b -glucuronide) were isolated from the aerial parts of Thymus sipyleus subsp. sipyleusvar. sipyleus and identified by spectroscopic methods. In vitro lipid peroxidation inhibition effects of the compounds were determined using TBA test method in a bovine brain liposome system. All compounds inhibited lipid peroxidation in various degrees except for ursolic acid. The order of the lipid peroxidation activities of luteolin and its glycosides were: Luteolin 7-O- b -glucuronide> luteolin 5-O- b -glucopyranoside> luteolin 7-O-(6”-feruloyl)- b -glucopyranoside > rosmarinic acid >luteolin. However, the activity order of the compounds was completely different in DPPH radical-scavenging activity. None of the compounds shows Fe chelating activity. The results were discussed based on their chemical structures and polarities.

The crude MeOH extract prepared from the aerial parts of G. stepporum and its EtOAc, n-BuOH, H 2O subextracts were screened for their inhibitory activity on H 2O 2-induced lipid peroxidation in human red blood cells. The EtOAc subextract was found to be the most active one and its chemical composition was further analysed. Six polyphenolic secondary metabolites including quercetin (1) , rutin (2) , methyl gallate (3) , pusilagin (4) , 1,3,6-tri- O -galloyl- β -glucospyranose (5) and 1,2,3,4,6-penta- O -galloyl- β -glucopyranose (6) were isolated from the EtOAc extract by successive chromatographic methods ( Sephadex CC, silica gel CC and P-TLC). The structures of the isolates were elucidated by 1D- and 2D-NMR and MS. This is the first report of occurrence of hydrolysable tannins in G. stepporum .

Many local vegetable materials are under-exploited because of inadequate scientific knowledge of their nutritional potentials. For this reason, the nutritional, phytochemical, antioxidant and antibacterial activities of the acetone, methanol and water extracts of the leaves of Sonchus asper and Sonchus oleraceus were investigated. The proximate analysis showed that the plants contained appreciable percentage of moisture content, ash content, crude protein, crude lipid, crude fibre and carbohydrate. The plants are also rich in minerals, flavonoids, flavonols, proanthocyanidins, total phenols and low levels of saponins, phytate and alkaloids. The extracts of the 2 plants also showed strong antioxidant antibacterial properties.

 The aim of this study was to investigate in vitro antioxidant, anticholinesterase and antibacterial activities of the petroleum ether, chloroform and methanol extracts obtained from the aerial parts of Jurinea consanguinea DC. (Asteraceae). Total phenolic and flavonoid contents of these crude extracts were determined as pyrocatechol and quercetin equivalents, respectively. The methanol extract which possessed almost the same effect with the chloroform extract in b -carotene-linoleic acid system exhibited higher free radical scavenging activity than a standard compound, BHT, at 100 and 200 m g/mL concentrations. The petroleum ether extract showed the highest acetylcholinesterase inhibitory activity among the tested extracts. The methanol extract exhibited higher butyrylcholinesterase inhibitory activity than galantamine at all concentrations (94% inhibition at 200 m g/mL). The antibacterial activity of the extracts was determined by the disc diffusion method. The chloroform extract showed moderate activity against B. subtilis, P. aeruginosa and S. aureus.

 Eleven flavonols have been isolated from the aerial parts of Ammi visnaga L. from which four aglycones, four monoglycosides, two diglycosides and one triglycoside. The flavonoid aglycones were distributed into one hydroxylated, quercetin (1) and three methoxylated, namely, rhamnetin (2), isorhamnetin (3) and rhamnazin (4). Among the monoglycosides, we found three 3-O-glucosides respectively linked to rhamnetin (5), isorhamnetin (6) and rhamnazin (7) and one 7-O-glucoside of isorhamnetin (8). The two diglycosides were 3-O-rutin of quercetin (9) and isorhamnetin (10) while the single trioside was quercetin 7,3,3’-O-triglucoside (11). These flavonols are reported for the first time from A. visnaga L . Free radical DPPH scavenging potential of the butanolic extract was investigated.

The leaves of Garcinia rigida afforded six triterpenoid compounds, friedelin (1), lanosta-8,25-en-3 b -ol (2), stigmasterol (3), lupeol (4), 3 b -hydroxy-20(29)-en-lupan-30-al (5) and 3 b -hydroxy-20(29)-en-lupan-30-ol (6). The structures of 1-6 were elucidated by IR, MS, NMR spectroscopies and comparison of their spectroscopic data with those reported in the literatures. Compound 6 showed toxicity to Artemia salina in brine shrimp lethality test (BLST) with LC 50 27.72 µg/mL.

The leaves of Lantana montevidensis Briq. (Verbenaceae) were subjected to hydrodistillation, and the essential oil extracted was examined with respect to chemical composition, antibacterial and antibiotic modifying activity by gaseous contact. Among the 19 identified components, β- caryophyllene (31.50%) , germacrene D (27.50%) and bicyclogermacrene (13.93%) were the main constituents. The essential oil volatile constituents inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa with a MID o 0.25 and > 1 mg/L, respectively. The activity of the antibiotics gentamicin and amikacin was reinforced against S. aureus and P. aeruginosa (with a 102% of amikacin activity against P. aeruginosa) after contact with the volatile components, showing that this oil influences the activity of the antibiotic and may be used as an adjuvant in the antibiotic therapy of respiratory tract bacterial pathogens.

The genus Hibiscus plants have different uses, some are used as foods (H. esculenta L.), and some species as remedy in traditional medicine (H. sabdariffa L.) as well as a colorant for herbal teas. The only species that grows naturally in Turkey is H. trionum L. The plant especially infests soy and corn fields, and therefore it is considered to be a noxious weed. The plant is also found to be a host for Potato Virus Y (PVY) and Tomato Spotted Wilt Virus (TSWV). Infestation of the crop fields by this plant shows that it germinates easily. Since it produces many seeds, distribution of the plant is also quiet easy. Though, seed oil yield is low (4.7%) since linoleic acid composition of the seed oil is quiet high (67,5%), it can still be used as a source of unsaturated fatty acids. The other major fatty acids are palmitic, oleic and stearic acids in the studied seed oil .

The composition of the essential oil extracted from Valeriana hardwickii Wall. roots growing wild in Talle Valley of Arunachal Pradesh, Eastern Himalaya was analyzed by capillary GC and GC/MS. Thirty-one compounds representing 89.6% of the total oil were identified. The oil was found to be rich in sesquiterpenes from which oxygenated sesquiterpenes (25.7%). Methyl linoleate (21.1%) and Valeracetate (11.6%) were the major constituents present in the oil. Whereas, Bornyl acetate (11.2%) and α-Terpinyl acetate (4.7%) were the only oxygenated monoterpenes identified in the investigated sample. Essential oil and its constituents of V. hardwickii may be used as the substitute of highly traded Indian Valerian (V. jatamansi) and European V. officinalis.