Mary C. Setzer

The Medicinal Value of Tropical Rainforest Plants from Paluma, North Queensland, Australia

A pharmacological survey of flora of the Paluma rainforest including 90 species representing 19 families has been carried out. Crude plant extracts have been screened for cytotoxic, antibacterial, antifungal, and antiviral activity, as well as brine shrimp lethality. Of these, 27 extracts exhibited remarkable cytotoxic activity, 23 showed antimicrobial activity, and 7 showed promising antiviral activity. Thus, 53 of the plant species examined showed marked bioactivity in one or more bioassays; a “hit rate” of 59%. These results underscore the phytomedicinal potential of Australian tropical rainforests.

Natural Products as New Treatment Options for Trichomoniasis: A Molecular Docking Investigation

Trichomoniasis, caused by the parasitic protozoan Trichomonas vaginalis, is the most common non-viral sexually-transmitted disease, and there can be severe complications from trichomoniasis. Antibiotic resistance in T. vaginalis is increasing, but there are currently no alternatives treatment options. There is a need to discover and develop new chemotherapeutic alternatives. Plant-derived natural products have long served as sources for new medicinal agents, as well as new leads for drug discovery and development. In this work, we have carried out an in silico screening of 952 antiprotozoal phytochemicals with specific protein drug targets of T. vaginalis. A total of 42 compounds showed remarkable docking properties to T. vaginalis methionine gamma-lyase (TvMGL) and to T. vaginalis purine nucleoside phosphorylase (TvPNP). The most promising ligands were polyphenolic compounds, and several of these showed docking properties superior to either co-crystallized ligands or synthetic enzyme inhibitors.

Triterpenoid Constituents in the Bark of Balanops australiana

Two new triterpenoid natural products (friedelane-3,21α-diol and friedelane-3α,28,29-triol) have been isolated from the chloroform bark extract of Balanops australiana from Paluma, north Queensland, Australia. The known triterpenoids betulinic acid, friedelin, canophyllol, zeylanol and 21α-hydroxyfriedelan-3-one were also isolated. The structures of the compounds were elucidated on the basis of spectral analysis. A single-crystal X-ray structural analysis has been carried out on 21α-hydroxyfriedelan-3-one.

Isolation and Characterization of a Stilbene-degrading Strain of Pseudomonas fluorescens, and Production of Antioxidant Compounds by Stilbene Metabolism

In this study, we consider the use of hydrocarbon-degrading bacteria that degrade trans-stilbene as a novel approach for synthesizing potentially bioactive hydroxylated stilbenes. A trans-stilbene-degrading bacterium, MN2, was isolated from activated sludge through enrichment culture, and identified as Pseudomonas fluorescens using conventional techniques. Degradation of trans-stilbene by this strain yielded two metabolites that had significant antioxidant activity.

Tabebuia bahamensis: A Major Source of Pharmacologically Important Ursolic Acid

Leaves of Tabebuia bahamensis, collected on Abaco Island, Bahamas, were dried and extracted with dichloromethane to yield a crude extract. Using preparative flash column chromatography on silica gel, enabled the isolation of ursolic acid with an excellent yield of 2.06 percent based on the mass of dry leaves. Both the crude leaf extract and ursolic acid produced selective in-vitro cytotoxic activity on tumor cells from human mammary and bladder tissue. Ursolic acid also demonstrated antibacterial activity against Staphylococcus aureus. INTRODUCTION Commonly known as “five fingers,” Tabebuia bahamensis (North.) Britton, is a small tree in the Bignoniaceae family along with 110 other genera consisting of 650 species of flowering plants of which about 100 species belong to the Tabebuia genus (Rahmatullah et al., 2010; Ospina et al., 2013). The Five Fingers tree, which is endemic to the Bahamas, is now commonly observed in tropical and subtropical habitats, has small leaves with 3-5 leaflets that are slender, green on the upper surface and strongly whitish on the lower surface. The tree is slim with straight upright branches and grows well in properly drained, alkaline or acidic soils. Flowers vary in color from white to pink and the tree blooms throughout the year (Popenoe, 1980). Several species of the genus Tabebuia hold ethnopharmacological and ethnobotanical importance. In the Bahamas, the leaves of T. bahamensis are used as a tea for “bodily strain” and for relief of backache (Higgs, 1969). The leaf decoction of T. bahamensis has been used as a sex stimulant and aphrodisiac (Halberstein, 2005), and the plant has been an essential component of a “love potion” prepared on Andros Island of the Bahamas (Eshbaugh, 2014). In the current study, the biological activity of crude leaf extract from T. bahamensis and the isolation of ursolic acid in large quantities are detailed. To our knowledge, this is the first examination of the phytochemistry of T. bahamensis. MATERIALS AND METHODS Plant material. Leaves of T. bahamensis were collected December 16, 2000, on Abaco Island, Bahamas (26° 31.092′ N, 77° 4.258 W, 13 m asl). The plant was identified in the field by a qualified local ethnobotanical informant (Dolly Davis), and verified with a field guide (Nickrent et al., 1991). A voucher specimen (TABA2000) has been deposited in the herbarium of the University of Alabama in Huntsville. The leaves were cleaned of debris, chopped, air dried, and 594 g of chopped dry leaves were extracted by refluxing with dichloromethane for four hours using a Soxhlet extractor. The solvent was subsequently evaporated to yield 50.1 g of crude leaf extract. Preparative flash chromatography. The crude, dichloromethane leaf extract (25.0 g) was subjected to flash chromatography (Figure 1) using silica gel (230-400 mesh), in a 90 cm long × 5 cm diameter glass column. A hexane/ethyl acetate step Shrestha et al.: Tabebuia bahamensis: A Major Source of Pharmacologically Importa