1.0 INTRODUCTION:

Herbs and products containing herb(s) have been in trade and commerce and are currently used for a variety of purposes.¹ The WHO defines an herb as being fresh or dried, fragmented or powdered plant material, which can be used in this crude state or further processed and formulated to become the final herbal product².In India, drugs of herbal origin have been used in traditional systems of medicines such as Unani and Ayurveda since ancient times. The Ayurveda system of medicine uses about 700 species, Unani 700, Siddha 600, Amchi 600 and modern medicine around 30 species.³

In the global context, herbal medicines flourish as the method of therapy of choice in many parts of the world. In recent years, the increasing demand for herbal medicines is being fueled by a growing consumer interest in natural products. Now it is finding new popularity as an alternative conventional medicine even in the industrialized countries and the adoption of crude extracts of plants for self-medication by the general public is in the increase.⁴

Over the past decade several news-catching episodes in developed communities indicated adverse effects, sometimes life threatening, allegedly arisen consequential to taking of OTC herbal products or traditional medicines from various ethnic groups. These OTC products may be contaminated with excessive or banned pesticides, microbial contaminants, heavy metals, chemical toxins, and for adulterated with orthodox drugs^. Excessive or banned pesticides, heavy metals and microbial contaminants may be related to the source of these herbal materials, if they are grown under contaminated environment or during collection of these plant materials. Chemical toxins may come from unfavorable or wrong storage conditions or chemical treatment due to storage. The presence of orthodox drugs can be related to unprofessional practice of manufacturers. Some of these environment related factors can be controlled by implementing standard operating procedures (SOP) leading to Good Agricultural Practice (GAP), Good Laboratory Practice (GLP), Good Supply Practice (GSP) and Good Manufacturing Practice (GMP) for producing these medicinal products from herbal or natural sources. The public’s belief that herbal and natural products are safer than synthetic medicines can only be ascertained by imposing regulatory standards on these products that should be manufactured using this Good Practices.⁵

The manufacture of the finished products should be in accordance with the good manufacturing practices (GMPs), with post-marketing quality assurance surveillance Evaluation of the toxicity and adverse drug reaction of the herbal preparation has been a neglected area, as herbs are considered natural products and, therefore safe. This lack of information makes it difficult to compare the benefit-risk profile of herbal medicines. Besides, the comparison of traditional medicines with modern drugs with comparative efficacy has not been conducted for most of the drugs.⁶

WHO, (1998) mentions maximum permissible limits in raw materials only for arsenic, cadmium, and lead, which amount to 1.0, 0.3, and 10 ppm, respectively. The concentration of heavy metals is one of the criteria that make raw plants admissible to the production of medicines due to the fact that amount taken increases with the concentration, increased by constant mass of a taken dose.⁷

Herbal medications are claimed and widely believed to be beneficial; however, there have been reports of acute and chronic intoxications resulting from their use. The popularity and availability of the traditional remedies have generated concerns regarding the safety, efficacy and responsibility of practitioners using traditional remedies. A common misperception is that medicaments of natural substances cannot be present in toxic concentrations in a variety of herbal preparations and dietary supplements⁸

Arsenic

Arsenic is a highly toxic, naturally occurring grayish- white element used as a poison in pesticides and herbicides. Arsenic is also found as an ingredient in pigments and wood preservatives. Arsenic contained in wolmanized lumber will not release toxic compounds unless burned. Arsenic can be harmful through inhalation, absorption through skin and mucous membranes, skin contact, and ingestion.⁹

Cadmium

Cadmium is a toxic heavy metal, well known for its occupational health risk, and cadmium (as a pollutant of air and water) is an increasing public health concern. Inhalation of cadmium fumes or dust is the primary cause of cadmium exposure¹⁰

Most studies have centered on the detection of early signs of kidney dysfunction and lung impairment in the occupational setting, and, in Japan, on the detection and screening for bone disease in general populations exposed to cadmium-contaminated rice. More recently, the possible role of cadmium in human carcinogenesis has also been studied in some detail.¹¹

Lead

Lead is a ubiquitous toxicant. Lead poisoning is an insidious disease that can result in developmental delays, behavioral disorders and irreversible brain damage. The major signs and symptoms of lead poisoning are pallor, gingival lead line, gastrointestinal disorder, and anemia, renal and neurological symptoms (peripheral neuropathy, ataxia and memory loss) in adults. Chronic exposure to lead is associated with renal dysfunction whilst, chronic lead toxicity will also lead to sterility in adults.¹²

2.0 MARKETED HERBAL FORMULATIONS SELECTED FOR STUDY:

Each tablet contains: Pravalpishti, Agasthibhasma, Andatwakpishti and amalaki (Embellica officinalis) 50mg each, Mandoorbhasma 15mg, Suvarna makshik Bhasma 10mg, Binders and Excipients q.s.

3.0 MATERIALS AND METHODS:

All 10 samples were analyzed for toxic metal contamination

Determination of Heavy Metals in Herbal Formulations

Study Design

An experimental method of research was performed to assess the presence or absence of heavy metals in selected Herbal formulations; and the concentration of each heavy metal was determined by AAS method. The formulations were given code i.e HT1 to HT10.

Preparation of Standards

Arsenic standard solution

Arsenic standard solution was prepared from Stock solution (1000 ppm Reagecon stock solution) standard solution of concentrations 0.02, 0.04, 0.06,.0.08 ppm were prepared The absorption of standard solution was measured at 193 nm using hallow cathode lamp as a light source and air acetylene flame with N2 gas source on Hydride generator mode on Atomic absorption Spectrophometer. The results are expressed as follows

The results are expressed as follows

Table No.1.Concentration and absorbance of Arsenic

Solution .No	Concentration	Absorbance
01	0.02	0.066
02	0.04	0.152
03	0.06	0.238
04	0.08	0.298
05	0.10	0.384

Fig No 1. Calibration Curve of Arsenic

Cadmium Standard solution:

Cadmium standard solutions were prepared from Stock solution (1000 ppm Reagecon stock solution) standard solution of concentrations 0.2, 0.4, 0.6, 0.8 and 1.0 ppm were prepared. The absorption of standard solution measured at 228.8 nm using hallow cathode lamp as a light source and air acetylene blue flame on Atomic absorption Spectrophometer. The results are expressed as follows

Table No.2 Concentration and absorbance of Cadmium

Solution .No	Concentration	Absorbance
1	0.200	0.034
2	0.400	0.051
3	0.600	0.080
4	0.800	0.106
5	1.000	0.129

Fig.No.2.Calibration curve of Cadmium

Lead standard solution:

Lead standard solutions were prepared from Stock solution (1000 ppm Reagecon stock solution) standard solution of concentrations,2, 4, 6.8,10 ppm., were prepared. The absorption of standard solution measured at 217 nm using hallow cathode lamp as a light source and acetylene blue flame on Atomic absorption Spectrophometer. The results are expressed as follows

The results are expressed as follows

Table No.3. Concentration and absorbance of Lead

Solution .No	Concentration	Absorbance
1	2.000	0.027
2	4.000	0.062
3	6.000	0.094
4	8.000	0.131
5	10.000	0.164

Fig.No.3. Calibration curve of lead

Calibration of Equipment

For the studied elements we established the following sensitivity and detection limits, respectively of the used flame atomic absorption Spectrophotometer (AAS) apparatus. As 0.02 and 0.08 ppm, Cd 0.2 and 1.0 ppm, Pb 2 and 10.0 ppm

Extraction of heavy metals from Herbal formulations:

A sample of 10gm of each herbal formulation was taken in a silica crucible and heated to remove the moisture. It was then put in a muffle furnace at 450°C, for 2 hours, to remove the organic material. The ash was digested in 5 ml dilute HCL + 1ml HNO₃, cool, 20 ml distilled water added. Filtered and the filter paper were washed distilled water, in 100ml volumetric flask. It was made to 100ml with distilled water and suitable dilutions were prepared. This filtrate contained the metal-like arsenic, lead cadmium. The Arsenic, cadmium and Lead were determined by Atomic Absorption Sphectrophometer.¹⁵

5.0 RESULTS:

Table No 4: Arsenic content in Herbal formulation code HT1 to HT10

Formulation code	Arsenic content (ppm)	Remark
HT1	0.28	Within permissible limit
HT2	0.56	Within permissible limit
HT3	0.034	Within permissible limit
HT4	0.06	Within permissible limit
HT5	0.73	Within permissible limit
HT6	0.02	Within permissible limit
HT7	0.04	Within permissible limit
HT8	0.05	Within permissible limit
HT9	0.021	Within permissible limit
HT10	0.06	Within permissible limit

Determination of Arsenic Content

Fig.No 4: Arsenic content in Herbal formulation HT1 to HT10

Determination of Cadmium Content

Table No 5: Cadmium content in Herbal formulation code HT1 to HT10

Formulation code	Cadmium content (ppm)	Remark
HT1	0.93	Above permissible limit
HT2	BDL	within permissible limit
HT3	0.56	Above permissible limit
HT4	0.75	Above permissible limit
HT5	0.29	Above permissible limit
HT6	0.29	Above permissible limit
HT7	BDL	within permissible limit
HT8	1.2	Above permissible limit
HT9	0.9	Above permissible limit
HT10	0.7	Above permissible limit

BDL=Below detectable limit

Fig No 5: Cadmium content in Herbal formulation HT1 to HT10

Determination of Lead Content

Table No 6: Lead content in Herbal formulation code H1 to H10

Formulation code	Lead content (ppm)	Remark
HT1	12.5	Above permissible limit
HT2	11.7	Above permissible limit
HT3	12.9	Above permissible limit
HT4	4.8	within permissible limit
HT5	6.2	within permissible limit
HT6	15.5	Above permissible limit
HT7	6.3	within permissible limit
HT8	1.9	within permissible limit
HT9	15.9	Above permissible limit
HT10	3.2	within permissible limit

BDL= Below detectable limit

Fig.No 6 Lead content in Herbal formulation code HT1 to HT10

Table No 7: Comparative data of Heavy metals contents in formulation code HT1 to HT10

Formulation code	Heavy metal content mg/kg
Formulation code	Arsenic	Cadmium	Lead
HT1	0.28	0.93	12.5
HT2	0.56	BDL	11.7
HT3	0.034	0.56	12.9
HT4	0.06	0.75	4.8
HT5	0.73	0.29	6.2
HT6	0.02	0.29	15.5
HT7	0.04	BDL	6.3
HT8	0.05	1.2	1.9
HT9	0.021	0.9	15.9
HT10	0.06	0.7	3.2

6.0 DISCUSSION:

People generally use herbal medicine for prolonged period of time to achieve desirable effects. Prolong consumption of such herbal medicine might reduce chronic or subtle health hazards. Thus our findings indicate that the medicinal plant or plant parts used for different diseases must be checked for heavy metals contamination in order to make it safe for human consumption.

The general belief that herbal preparations are natural and, therefore, inherently safe harmless and without any adverse effects is sometimes unfounded. Toxic effects of herbal preparations have been attributed to several factors including contamination by poisoning through traditional Chinese, Indian and Malaysian medicines have been reported.

WHO, (1998) mentions maximum permissible limits in raw materials only for arsenic, cadmium, and lead, which amount to 1.0, 0.3, and 10 ppm, respectively. The present work indicates that there is presence of Heavy Metal contents in Herbal formulations selected for study. It is found that Arsenic content in Herbal formulations was below the Permissible limit in all formulations.The Cadmium content in HT1 (0.93 ppm), HT3 (0.56 ppm), HT4 (0. 75 ppm), HT8 (1.2 ppm), HT9 (0.9 ppm), and H10 (0.7 ppm) which are above the permissible limits. The lead content in HT1,(12.7 ppm),HT2 (11.7ppm ),HT3 (12.9 ppm),HT6 (15.5 ppm),HT9 and (15.9 ppm) which are above the permissible limits. Such formulations are injurious to health of patient if consumed regularly.

7.0 ACKNOWLEDGEMENT:

The author is thankful to Chairman, P. Wadhwani College of Pharmacy for providing necessary support for doing this research work.

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Received on 21.02.2014 Accepted on 10.03.2014

Asian J. Pharm. Ana. 4(1): Jan.-Mar. 2014; Page 11-16