HPLC-coupled spectroscopic techniques (UV, MS, NMR) for the structure elucidation of phthalides in Ligusticum chuanxiong.

Ligusticum chuanxiong Hort., a plant that is frequently used in traditional Chinese medicine, has been studied using HPLC-coupled spectroscopic techniques such as HPLC-UV, HPLC-MS as well as HPLC-NMR. With the aid of these modern spectroscopic techniques, the main constituents, namely senkyunolide A, butylphthalide, neocnidilide and Z-ligustilide, have been characterized and identified. Phthalide dimers, present in smaller amounts, have been identified by HPLC-UV and HPLC-MS analysis and compared with reference compounds. Stereochemical features of some phthalide monomers have been determined by detailed spectroscopic studies for the first time.

Cryptocarya species--substitute plants for Ocotea bullata? A pharmacological investigation in terms of cyclooxygenase-1 and -2 inhibition.

In response to the serious scarcity of Ocotea bullata (Burch.) Baillon (Lauraceae), an important medicinal plant in South Africa, Cryptocarya species (Lauraceae) are frequently used as substitute plants. Our investigation was aimed at a pharmacological comparison of O. bullata and the Cryptocarya species C. latifolia Sonder, C. myrtifolia Stapf., C. transvaalensis Burtt Davy, C. woodii Engl. and C. wyliei Stapf., in terms of in vitro cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) inhibition, as an indication of O. bullatas' repute as a remedy against headache. Furthermore, we also compared bark and leaf extracts of the species investigated in order to address the problem of destructive ring-barking. The utilization of leaves instead of bark would help in the management of threatened medicinal plants. All Cryptocarya species were superior to O. bullata with regard to bark extracts. C. woodii bark extracts showed outstanding equipotent activity towards COX-1 and COX-2. The activity of extracts of fresh leaves was comparable to the activity of the respective bark extracts. Drying the leaves before extraction resulted in a loss of activity, with the exception of C. wyliei. Extracts of dried C. wyliei leaves exhibited high inhibitory activity, with a COX-2/COX-1 ratio of 5.8.

Stereostructure and anti-inflammatory activity of three diastereomers of ocobullenone from Ocotea bullata.

A novel diastereomer of ocobullenone. designated as sibyllenone, was isolated from the stem bark of mature Ocotea bullata in the course of a search for anti-inflammatory compounds from this plant. The stereostructure was established by X-ray crystallography and corroborated by NOESY analysis. Ocobullenone, obtained previously, was re-isolated and crystallised successfully for X-ray analysis, thus making possible an accurate spatial comparison of ocobullenone, iso-ocobullenone and the new stereoisomer. Tested pharmacologically for cyclooxygenase-1 and 2, and 5-lipoxygenase inhibition, sibyllenone was the only compound from O. bullata which showed good inhibitory activity towards 5-lipoxygenase.

Analytical and pharmacological investigation of Ocotea bullata (black stinkwood) bark and leaves.

Ocotea bullata (Lauraceae), one of the top-ten traditional medicinal plants used in KwaZulu-Natal, is close to extinction through high demand and destructive harvesting methods. The stem bark is traditionally used to cure headaches, urinary disorders and stomach problems. Substitution of leaves for bark provides a possible resource management solution for this threatened medicinal plant. One aim of this study was to compare the chemical composition of O. bullata leaves and bark using TLC, HPLC and GC-MS analysis. The characteristic analytical fingerprints of leaf and bark extracts showed great similarities. A second aim was to investigate the pharmacological properties of O. bullata as a remedy against headaches. Leaf and bark extracts were tested in terms of cyclooxygenase-1 and 5-lipoxygenase inhibition. Extracts from the bark exhibited moderate inhibitory activity in both test systems. Extracts from fresh leaves were superior to bark extracts in terms of their in vitro inhibitory activity against cyclooxygenase-1 and 5-lipoxygenase. Volatiles obtained from n-hexane extracts of leaves and bark showed better inhibitory activity towards cyclooxygenase-1 and especially towards 5-lipoxygenase than the original n-hexane extracts. Volatiles were therefore recognized as one of the main active principles in O. bullata with regards to the anti-inflammatory properties of this medicinal plant. This lends support to the traditional usage of O. bullata bark as an inhalant or snuff.

Plant part substitution--a way to conserve endangered medicinal plants?

Population growth, urbanization and the unrestricted collection of medicinal plants from the wild is resulting in an over-exploitation of natural resources in southern Africa. Therefore, the management of traditional medicinal plant resources has become a matter of urgency. In southern Africa the most frequently used medicinal plants are slow-growing forest trees, bulbous and tuberous plants, with bark and underground parts being the parts mainly utilized. A strategy which would satisfy the requirements of sustainable harvesting, yet simultaneously provide for primary health care needs, would be the substitution of bark or underground parts with leaves of the same plant. This paper outlines the concept of plant substitution, using preliminary results of our recent investigations into four of the most important and most threatened South African medicinal plants - Eucomis autumnalis (bulb), Siphonochilus aethiopicus (rhizome), Ocotea bullata (bark), and Warburgia salutaris (bark) - as a demonstration of the kind of research necessary. Extracts of various plant parts were compared chemically using TLC-analysis, and pharmacologically in terms of antibacterial activity and cyclooxygenase-1 inhibition in vitro. The importance of the concept of plant part substitution as a strategy for the conservation of medicinal plants in southern Africa is discussed in terms of the results obtained.

Inhibitory effects of Angelica pubescens f. biserrata on 5-lipoxygenase and cyclooxygenase.

Linoleic acid, osthol, osthenol and two polyacetylenes, falcarindiol and 11(S),16(R)-dihydroxyoctadeca-9Z,17-diene-12,14-diyn-1 -yl acetate were found to be the most active compounds responsible for the inhibitory activity of the dichloromethane extract of the roots of Angelica pubescens f. biserrata on 5-lipoxygenase (5-LO) and cyclooxygenase (COX-1) in vitro. They showed prominent inhibitory effect on 5-LO with IC50 values of 27.9 microM, 36.2 microM, 43.1 microM, 9.4 microM and 24.0 microM, respectively. Linoleic acid, osthenol, falcarindiol and 11(S), 16(R)-dihydroxyoctadeca-9Z,17-diene-12,14-diyn-1-yl acetate exhibited inhibitory activity on COX-1 with IC50 values of 13.3 microM, 64.3 microM, 66.0 microM and 73.3 microM.

5-Lipoxygenase and cyclooxygenase inhibitory active constituents from Qianghuo (Notopterygium incisum).

The n-hexane extract of Qianghuo (underground parts of Notopterygium incisum Ting x H.T. Chang, Umbelliferae) showed inhibitory activity in vitro in 5-lipoxygenase (5-LO) and cyclooxygenase (COS) assays. Two major constituents, phenethyl ferulate and falcarindiol, and one minor compound (-)-bornyl ferulate, were identified as the main active principles. The correlation between the content of active constituents and the inhibitory activity of the extracts was examined with seven commercial drug samples from different sources. It was obvious that the content of phenethyl ferulate was mainly responsible for the COX inhibitory activity of the extracts and falcarindiol for 5-LO inhibitory activity. Since the main active constituents phenethyl ferulate and falcarindiol can easily be quantified by HPLC, this is a suitable method for standardization and characterization of the drug.