Green Gold from Down Under

Green Gold from Down Under
Bioprospecting for Phytopharmaceuticals
from Tropical North Queensland Australia

Australia has a unique and distinctive flora. A long period of isolation has led to a high proportion of endemic species and genera.  Our research has concentrated on the rainforests of the wet tropics of north-eastern Queensland.  This region, stretching from Townsville north to Cooktown, contains the largest area of extant rainforest in Australia and consists of coastal plains as well as several mountain ranges and tablelands.

daintree-river daintree-natl-park
Daintree River, far north Queensland Daintree National Park, far north Queensland
paluma-rainforest iron-range-natl-park
Paluma Rainforest Iron Range National Park, Cape York Peninsula

Some representative publications describing our work in north Queensland

Setzer WN, Setzer MC, Peppers RL, McFerrin MB, Meehan EJ, Chen L, Bates RB, Nakkiew P, Jackes BR.  2000.  Triterpenoid Constituents in the Bark of Balanops australiana.  Australian Journal of Chemistry  53: 809-812.

Two new triterpenoid natural products (friedelane-3a,21a-diol and friedelane-3a,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 21a-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 21a-hydroxyfriedelan-3-one.

balanops-australiana hydroxyfriedelan
Balanops australiana 21α-hydroxyfriedelan-3-one 

Setzer WN, Setzer MC, Bates RB, Jackes BR.  2000.  Biologically active triterpenoids of Syncarpia glomulifera bark extract from Paluma, north Queensland, Australia. Planta Medica  66: 176-177.

The crude chloroform bark extract of Syncarpia glomulifera (Myrtaceae) shows antibacterial and cytotoxic activity.  Bioactivity-directed separation led to the isolation of oleanolic acid-3-acetate, ursolic acid-3-acetate and betulinic acid.  The relatively large abundance (10% of the crude extract) and high degree of activity of betulinic acid are responsible for the bioactivity of the crude bark extract.

syncarpia-glomulifera betulinic-acid
Syncarpia glomulifera  Betulinic acid

Setzer MC, Setzer WN, Jackes BR, Gentry GA, Moriarity DM.  2001.  The medicinal value of tropical rainforest plants from Paluma, north Queensland, Australia. Pharmaceutical Biology  39: 67-71.

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.

Setzer WN, Petty JL, Schmidt JM, Setzer MC, Bates RB, Jackes BR.  2004.  Bioactive lupane triterpenoids in Alphitonia petriei from Paluma, north Queensland, Australia.  Current Topics in Phytochemistry  6: 145-148. 

The crude chloroform extract of the bark of Alphitonia petriei (Rhamnaceae), collected from the Paluma Rainforest, north Queensland, Australia, exhibits cytotoxic activity against MDA-MB-231 (human mammary adenocarcinoma), MCF-7 (human mammary adenocarcinoma), and 5637 (human primary bladder carcinoma) cells. The extract also shows antibacterial activity against Bacillus cereus.  Bioactivity-directed separation led to the isolation of 2-ketobetulonic acid and betulinic acid as the bioactive components.

ap-leaves-fruit ap-bark-blaze
Alphitonia petriei leaves and fruit Alphitonia petriei bark with blaze 
2-Ketobetulnic acid

Setzer WN, Rozmus GF, Setzer MC, Schmidt JM, Vogler B, Reeb S, Betsy R. Jackes BR, Irvine AK.  2005.  Bioactive principles in the bark of Pilidiostigma tropicum. Journal of Molecular Modeling  11: in press.

The crude dichloromethane bark extract of Pilidiostigma tropicum (Myrtaceae) from north Queensland, Australia, shows antibacterial and cytotoxic activity. Bioactivity-directed separation led to the isolation of rhodomyrtoxin B and ursolic acid-3-p-coumarate as the biologically active materials. The structures of these compounds were elucidated on the basis of spectral analysis.  The intercalation interaction of rhodomyrtoxin B with DNA was investigated using molecular mechanics and ab initio molecular orbital techniques.  A favorable p-p interaction between rhodomyrtoxin B and the cytosine-guanine base pair is predicted, but the orientation of the interaction cannot be predicted based on frontier molecular orbitals.

pilidiostigma-tropicum rhodomytrodxin-b
Pilidiostigma tropicum Rhodomytroxin B 

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