Medicinal plants as a possible source of toxic chemical exposure | |
| Author | Maneerat Khemkhao |
| Call Number | AIT Thesis no.EV-06-15 |
| Subject(s) | Medicinal plants--Thailand Poisonous plants--Toxicology--Thailand |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Inter-University Program on Environmental Toxicology, Technology and Management, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Centella asialica is an important medicinal herb that is widely used in the West and East. Folkloric reputation of this plant are as follows, it helps to improve reflexes, combats stress, and increase mental and physical power. C. asiatica is also used for high blood pressure, senility, aging, and helping the body to protect itself against toxins. However, C. usiaticu may be contaminated with sonic toxic heavy metals, especially cadmium from the soil, water, and organic fertilizers, especially from animal wastes. Ingestion of Cd contaminated C. usiatica can cause accumulation of this metal in the body, and may produce serious adverse effects. Therefore, the aim of this research is to determine cadmium concentrations contaminated in C. asiatica plant and its products, such as juice, nutraceutical capsules, and herbal teas. The Cd concentrations ill C. usiatica, a total of 52 samples were purchased from 23 different markets/ sources were determined. C. asiatica juice (32), nutraceutical capsules (4 brands), herbal teas (4 brands) were also purchased from different markets and Cd concentrations were analyzed. The maximum and mean levels of Cd in the C. aslatlca analyzed samples were 5.087 ±0.005, and 0.72 ±0.016 mgt kg, respectively. C. asiatica as vegetables were 42 out of 52 samples exceeded the limited standard value of Cd in medicinal plant (0.3 mg/kg). In herbal juice, the mean and maximum Cd levels were 6.238 ±0.171, and 21.75 a :1.250 p.g/l, respectively. Nevertheless, only 2 out of 32 samples were exceeded the limited standard value of FDA, US (10 g/1). For nutraceutical capsules, the maximum (0.825 ±0.029 mg kg) and mean value (0.402 ±0.003 mg/kg) of Cd were exceeded the limited value in medicinal plant. 100% of herbal teas samples were exceeded the standard value (0.003 mg/kg). The results of this study clearly indicated that majority of C. asiatica were contaminated with Cd. Therefore, C. asiatica regularly consumed as vegetable should be avoided. Further study was also conducted to examine the uptake of Cd by C. asiatica in contaminated soil under greenhouse condition. The effects of chemical amendments (calcium carbonate and compost) on the Cd uptake by C. asiatica in polluted soils were also studied. Low Cd-contaminated soil obtained from Ratchaburi province (0.981- 1.105 mg/kg), medium (39.78 mg/kg) and high Cd contaminated soil (56.83 mg/kg) were obtained from Tak province. The result obtained from the present study found that plant biomass was not significantly different. Root biomass was significantly different with low and medium Cd levels. Stems accumulated highest Cd following by leaves and roots, respectively. Excessive accumulation of Cd in agricultural soil may not only result in environmental contamination, but also increased Cd uptake by C. asiatica which may affect food quality and safety. Accumulation of Cd in all parts of C. asiatica increased significantly with a high Cd-contaminated soil. The effects of lime and compost application on contaminated soil samples were studied. It was found that lisle can reduce Cd uptake by C. asiatica better than compost. Low and medium Cd-contaminated soils could be reduced by using compost. However, high Cdcontaminated soil could not be reduced by this soil amendment method |
| Year | 2006 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Jutamaad Satayavivad; |
| Examination Committee(s) | Preeda Parkpain ;Nuchanart Rungkadilok |
| Scholarship Donor(s) | Chulabhorn Research Institute (CRI) Mahidol University (MU) Asian Institute of Technology (AIT) ; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2006 |