Aliphatic compounds from Curculigo orchioides rhizomes

21-Hydroxytetracontan-20-one and 4-methylheptadecanoic acid have been isolated from the rhizomes of Curculigo orchioides and characterized on the basis of chemical and spectroscopic evidence.     

Aliphatic hydroxyketones and diosgenin from Costus speciosus roots

Two new compounds, B and C, isolated from the roots of Costus speciosus have been characterized as 24-hydroxyhentriacontan-27-one and 24-hydroxytriacontan-26-one by spectral data and chemical studies. Methyl triacontanoate, diosgenin and sitosterol have also been isolated and identified.     

Aliphatic constituents from Duboisia myoporoides

Four new compounds, isolated from the leaves and stems of Duboisia myoporoides have been characterized as 6-methyldotriacontane, hentriacontanyl tetratriacontanoate, 3-hydroxydotriacontan-28-one and 4-pentatriacontanone, respectively, by spectral data and chemical studies.     

Oxo fatty acids from Cryptocoryne spiralis rhizomes

From the rhizomes of Cryptocoryne spiralis two new oxo fatty acids, 22-oxononacosanoic and 26-oxohentriacontanoic, have been isolated and their structure established by spectral data and chemical studies.     

Oxo fatty acid esters from Cryptocoryne spiralis rhizomes

Two new compounds, isolated from the rhizomes of Cryptocoryne spiralis, have been characterized as ethyl 14-oxotetracosanoate and 15-oxoeicosanyl 14-oxoheptadecanoate by spectral data and chemical studies. Hentriacontane and sitosterol have also been isolated and identified.     

Arylbenzofurans from Dalbergia parviflora

The isolation of two polysubstituted arylbenzofurans from the heartwood of Dalbergia parviflora is described. Their structures were elucidated mainly by spectroscopic techniques (UV, IR, ¹H and ¹³C NMR). They were named parvifuran (5-hydroxy-6-methoxy-3-methyl-2-phenylbenzofuran) and isoparvifuran (5-hydroxy-6-methoxy-2-methyl-3-phenylbenzofuran) and are the first compounds of this class isolated from a Dalbergia species.     

Aliphatic compounds from Hyoscyamus muticus

Four new compounds have been isolated in trace amounts from the leaves and stems of Hyoscyamus muticus and are characterized as 15-hydroxyheneicosa     

A new dihydrobenzofuran from Liatris provincialis

A chloroform extract of Liatris provincialis Godfrey gave as a minor component a new dihydrobenzofuran, whose structure was established as I.     

In vitro bulblet production of Brunsvigia undulata from twin-scales

Many South African medicinal plants are over-collected for use in traditional medicines. This necessitates developing methods for increasing production. Micropropagation can be used as an alternative to conventional propagation methods. Twin-scales, cut from large parent bulbs, were cultured on MS medium (Murashige and Skoog, 1962) supplemented with 25 plant growth regulator combinations. Bulblets formed on twin-scales in 24 of the treatments. All explants formed bulblets on plant growth regulator-free medium. The effect of plant growth regulators, activated charcoal, explant orientation, explant origin and photoperiod on bulblet production was investigated. Bulblet formation was greatest when twin-scales were excised from the middle of the parent bulb, placed adaxial side down on plant growth regulator-free medium and kept in a 16 h photoperiod.     

An aminopeptidase from Agave americana thermodynamic studies

Purified Agave aminopeptidase was characterized with respect to the thermodynamic properties of the reaction catalysed by the enzyme. Kinetic studies were conducted at different temperatures ranging from 7.8 to 45°. The energy of activation, E_a, as well as the constants ΔH, ΔF and ΔS were calculated for both the formation of the enzyme-substrate complex, and the dissociation of the enzyme-product complex. Kinetic studies in buffers with varying dielectric constants enabled the determination of the electrostatic as well as the non-electrostatic components of ΔS. These results fit well into the overall kinetic picture of this enzyme-catalysed reaction as reported previously.     

Sulphides and furanones from steam volatile oils of Allium fistulosum and Allium chinense

The constituents of the steam volatile oils from two kinds of Allium fistulosum, A. fistulosum var. caespitosum and A. chinense, have been investigated by GC and spectral techniques (IR, UV, GC/MS, ¹H NMR and ¹³C NMR). The compounds identified from the neutral fraction of each volatile oil included sulphides, thiolanes, alcohols, aldehydes, ketones, furanones and others. Among the sulphur compounds, dipropyl disulphide comprised ca 28% of A. fistulosum oil, ca 23% of A. fistulosum var. caespitosum oil and ca 30% of A. chinense oil. A. fistulosum oil was characterized by a large quantity of tridecan-2-one (ca 52%) and 2,3-dihydro-2-octyl-5-methylfuran-3-one (ca 16%). Also, a large amount of 2,3-dihydro-2-hexyl-5-methylfuran-3-one (ca 20%) was isolated from A. chinense oil.     

Aliphatic compounds from Costus speciosus roots

Two new compounds G and H isolated from the roots of Costus speciosus have been characterized as 8-hydroxytriacontan-25-one and Me tritriacontanoat     

Lactones,flavonoids and benzophenones from Garcinia conrauana and Garcinia mannii

Two novel lactones have been isolated from the stem barks of Garcinia conrauana and G. mannii. The major component of the bark of G. conrauana was identified as 3-(3$\text{,}\text{?}$ 3″-dimethylallyl)-conrauanalactone [4-hydroxy-3-(3″, 3″-dimethylallyl)-6-pentadecylpyran- 2-one] by comparison of spectral data of the isolated compound and two methylethers with that obtained for the previously isolated conrauanalactone. A minor component of the bark of G. mannii was tentatively identified as 3-α-hydroxy-5-(heptadec-8′-enyl)-tetrahydro- furan-2-one on the basis of spectral data from the isolated compound and its monoacetate. The distributions of biflavonoids and related compounds and benzophenones in the stem bark, heartwood, seeds and leaves of the two species are reported.     

Structure and synthesis of the growth inhibitor batatasin I from Dioscorea batatas

The synthesis of 6-hydroxy-2,4,7-trimethoxyphenanthrene is described and its identity with the growth inhibitor, batatasin I, is confirmed.     

A tropone derivative from orobanche rapum-genistae

A new tropone,3,8-dimethyl-5-isopropyl-2,3- dihydro(1H)azulen-6-one, named orobanone, has been isolated for the first time from a plant (Orobanche rapum-genistae, Orobanchaceae). This tropone is synthesized by the parasite and exists, with other related compounds, in various species of broom-rapes.     

Structure and biosynthesis of a new anthraquinone from Streptocarpus dunnii

A new anthraquinone (1-hydroxy-2-hydroxymethylanthraquinone has been isolated from the title plant. The structure was determined by spectroscopy and synthesis. Investigation on the biosynthesis showed that this quinone is formed via o-succinoylbenzoic acid.     

Properties and partial purification of mevalonate kinase from Agave americana

Mevalonate kinase activity was demonstrated in acetone powder extracts from Agave americana leaves, flowers and scape. ATP was the most effective phosphate donor. The enzyme had an optimum pH of 7.9 in Tris-HCl buffer. Dialysis decreased the ability to phosphorylate mevalonic acid (MVA). Partially purified mevalonate kinase reached maximum activity in the presence of 2 mM Mn²⁺ or 6–8 mM Mg²⁺. Higher concentrations of Mn²⁺ were inhibitory, whereas higher concentrations of Mg²⁺ produced only a small decrease in the activity. The amount of mevalonate-5-phosphate (MVAP) formed depended on protein concentration and incubation time. During short incubations, the MVAP formed increased as protein concentration rose, whereas during prolonged incubations (1–6 hr), there was a decrease in the MVAP formed when a certain amount of protein was exceeded. It is suggested that MVAP formed was hydrolysed by a phosphatase present in the extracts. This interfering activity was eliminated when mevalonate kinase is partially purified. The apparent K_m values of the enzyme from leaves were 0.05 mM for MVA and 0. 14 mM for ATP. Similar K_m values are obtained with partially purified mevalonate kinase. The enzyme was purified by ammonium sulphate precipitation, Sephadex G-100 filtration and DEAE-Sephadex A-50 fractionation.     

Multiple forms of peroxidase from Narcissus pseudonarcissus

Multiple forms of peroxidase from Narcissus pseudonarcissus were identified and separated by polyacrylamide gel electrophoresis. The enzyme forms were found to be particulate but could be solubilized in buffers of high ionic strength and high pH. Bulbs at different stages (dormant, early growth, flowering and post-flowering) were investigated and both the number and distribution of peroxidase forms were found to differ. The major peroxidase form in dormant bulbs was purified and displayed a number of notable properties including a MW of at least 10⁵, a high isoelectric point and the apparent absence of a heme prosthetic group.     

Systematic implications of the exocrine chemistry of some Hypoclinea species

The exocrine compounds produced by several species of Hypoclinea were analysed and compared to those identified in species in other genera of the ant subfamily Dolichoderinae. Two new natural products, 2-hydroxy-6-methylaceto-phenone and 2-acetoxy-6-methylacetophenone, were identified as anal gland products of three Hypoclinea species. The significance of two “forms” of H. bidens possessing completely different glandular secretions is discussed, and the relationship of the genera Hypoclinea and Dolichoderus is explored in terms of the exocrine chemistry of species in these two dolichoderine taxa.