Plants have an incredible diversity of compounds whose chemical structures are often unlikely to be synthesized in laboratories. These compounds, produced mainly for defence of the host plant have varied biological/medicinal potentials. The medicinal properties of . South Africa has America and India for several external and internal medical conditions
and has also shown anti cancer activity . Rooibos (Aspalathus linearis) has been
plants could be based on the antioxidant, antimicrobial, antipyretic effects of the phytochemicals in them 27,28. The efficacy of medicinal plants has encouraged chemists and pharmacists to carry out rigorous analysis on the plants and to establish a relationship between chemical composition and therapeutic activities. Although it has been acknowledged that plant based traditional medicine is one of the surest means of achieving total health care coverage of the world’s population, many plant species have not been
effectiveness and safety29,30. One of the species under investigation, Tarchonanthus camphoratus, has been reported to have many medicinal applications in traditional healing31-34. However, to the best knowledge of this researcher, there is no documented information about the chemical profiles of the volatile and non volatile constituents; the toxicity and therefore safety of T. camphoratus and of the other Tarchonanthusspecies of Kwa-Zulu Natal.
In South Africa malaria is categorised as seasonal and unstable, with the mosquitoes Anopheles arabiensisand Anopheles funestusbeing the major malaria vectors35. In the year 2005 the annual number of reported malaria cases was approximately 7755 while in 2006 it was 12,09836. The growing resistance of mosquitoes to insecticides is a potentially serious challenge to malaria vector control37. In South Africa, resistance to pyrethroids and DDT has been reported and the potential for carbamate resistance has been detected in Anopheles arabiensis37. This increased resistance, has paved the way for the investigation of botanical extracts for use in malaria vector control. Larval source reduction by habitat modification or use of larval control agents could be a less costly and a more effective strategy for eliminating mosquito larvae populations.
studied for biologically active secondary products and lack scientific proof of their
Methyl bromide and phosphine are the most commonly used fumigants for the control of stored product pests but methyl bromide depletes the ozone layer and was phased out completely by most countries in the early 2000s38. Cases of resistance to phosphine by some stored product insects have been reported39. Globally, the excessive use of synthetic insecticides in homes, croplands, urban environments and water bodies to get rid of noxious insects has resulted in an increased risk of insecticide resistance, enhanced pest resurgence, toxicological implications to human health and increased environmental pollution.
Combating environmental pollution and its ill-effects on life and life-support systems is one of the most serious challenges before the present day world. As an alternative, botanical pesticides are of great interest because they are natural pesticides and are safe to humans and the environment. T. camphoratus, one of the species under investigation, has been reported to have insecticidal properties mainly as a repellent40,41. The volatile and non volatile constituents of T. camphoratus and other Tarchonanthus species could contain compounds that are toxic to mosquito larvae and to stored grain pests or could repel insect pests.
Since the discovery of penicillin by Alexander Fleming in 1929, many new classes of antibiotics have become available for the treatment of bacterial infections, but due to the excessive and often unnecessary use of antibiotics in humans and animals, bacterial resistance has now been reported against every currently available antibiotic42,43. Plants could be a source of antibacterial agents to manage some of the emerging resistant microbial species. Viruses and bacteria do not become resistant to plant extracts as they do to modern day synthetic antibiotic drugs. It is not possible for the micrororganisms to mutate and adapt to the many chemical constituents found, for example, in essential oils
but can easily mutate and adapt to drugs because drugs are made by isolating one or two constituents to which a virus or bacteria can adopt44.Although the antibacterial activity of the volatile and non volatile extracts of T. camphoratus from different localities have been reported in literature30,45-49, no report has been cited on the antibacterial activity of T.
camphoratus andother Tarchonanthusspecies from Kwa-Zulu Natal.
Free radicals have been implicated as causative agents of many diseases and illnesses50. Many medicinal plants have been reported to have antioxidant activity. No research has so far been done on the antioxidant activity of the volatile and non volatile constituents of the Tarchonanthus species from Kwa-Zulu Natal. These species may possess potent bioactive compounds capable of preventing and treating most oxidative related diseases and may also serve as leads for the development of novel drugs.
Several plants used in traditional medicine can cause damage to genetic material and therefore have the potential to cause long-term damage in patients when administered as medical preparations51. There is recorded information about the toxic symptoms caused by plants when ingested by animals but very little is known about the toxicity of herbal remedies in man30. There is no recorded information about the poisoning activity of Tarchonanthus species but acute toxicity due to the use of traditional medicines is common in South Africa52. Approximately 43% of poisoning cases recorded in the forensic database in Johannesburg from 1991 to 1995 were caused by traditional plant medicines53. Therefore it is necessary that cytotoxicity screening of Tarchonanthus species is carried out alongside evaluation of their biological and chemical properties.
Like other medicinal plants, the Tarchonanthus species is not only a potential solution to human predicaments associated with the use of synthetic chemicals, but their volatile and non volatile constituents may contain compounds that could be used as drugs or act as leads in drug development.
The principal aim of the present study was to
volatile and non volatile constituents of the Tarchonanthus speciesof Kwa-Zulu Natal.
To extract the volatile constituents of theTarchonanthus species by means of hydro distillation.
To extract the non volatile constituents from the leaves and bark of the Tarchonanthusspecies by using solvents of different polarities.
To investigate the chemical composition of the volatile and non volatile constituents
To determine the antimicrobial activity of the volatile and non volatile constituents ofthe Tarchonanthusspecies and compare it with that of conventional antibiotics.
To determine the antioxidant potential of the volatile and non volatile constituents of the
To determine the insecticidal activity of the volatile constituents of the
To determine the chemical constituents and evaluate the biological activities of the
Tarchonanthus species.
Tarchonanthus species and compare it with that of known antioxidants.
Tarchonanthusspecies.
of the 1.2 Aim and Objectives of the Study
1.2.1 Specific Objectives of the Study
To determine the larvicidal activity of the volatile extracts of the Tarchonanthus species against Anopheles arabiensismosquito larvae.
To determine the cytotoxicity of the volatile and non volatile extracts of the Tarchonanthus species using the Brine shrimp lethality assay and the MTT assay.
1.Traditional medicine. World Health Organization. 2008-12-01. Available at:
http://www.who.int/mediacentre/factsheets/fs134/en/index.html.
2.Upton R. 1999. Traditional Chinese medicine and the Dietary Supplement Health and Education Act.
3. Sucher NJ., Carles MC. 2008. Genome-based approaches to the authentication of
4. World Health Organization. 2002. WHO Traditional medicine strategy 2002–2005.
Geneva. Available at: http://apps.who.int/medicinedocs/en/d/Js2297e/. Accessed February 2012.
5.Holtz C. 2007. Global health care: Issues and policies. Sudbury, MA, Jones & Bartlett Publishers.
6. Barnes PM., Bloom B., Nahin R. 2007. Complementary and alternative medicine use among adults and children: (National Health Statistics Report). Available at:
http://nccam.nih.gov/news/2008/nhsr12.pdf. Accessed March 2012.
7.WHO. 2008. Traditional Medicine Factsheet. Geneva, World Health Organization. Available Accessed March 2012.
8. Cunningham AB. 1997. An Africa-wide overview of Medicinal Plant Harvesting, Conservation and Healthcare , Non-Wood Forest Products. In: Medicinal plants for Forest Conservation and Healthcare. FAO, Italy.
9. Van Wyk BE., Van Oudtshoorn B., Gericke N.1997. Medicinal Plants of South Africa.
Pretoria, Briza Publications: 78–79.
10. Sofowora A. 1982. Medicinal plants and traditional medicine in Africa. John Wiley, Chichester pp. 179.
medicinal plants. Planta Medica. 74:603–623.
J Alt Comp Med. 5:115–118.
Accessed March 2012.
at: http://www.who.int/mediacentre/factsheets/fs134/en/.