Introduction

Now-a-days using plants for medical purposes become essential feature of the culture and the tradition. A Major part of the population depends directly on the traditional medicine for the primary health care. The use of higher plants and their extracts to treat infection is the usual practices. The biochemistry of herbs and the pharmacology of their various constituents is an aspect of phytotherapy that initiates many herbalists to do many researches. An investigation has been carried out to evaluate the pharmacognostic, phytochemical and biochemical aspect of Acalypha indica, Vitex negundo and Coriandrum sativum.

Materials and Methods

To assess the activity of selected medicinal plants, pharmacognostic studies like organoleptic study, fluorescences analysis, preliminary phytochemical studies and biochemical analysis were carried out. Organoleptic studies were based on method of Jackson and Snowdown (1968) and fluorescences properties following Kokoski et al (1958) and Chore and Pratt (1949). The biochemical parameters like protein (Lowry et al., 1951), carbohydrates (Hedge and Hofreiter, 1962), reducing sugar (Miller, 1972), total soluble sugar (Mahadevan and Sridhar, 1986) phenol (Malick and Singh, 1980) and chlorophylls (Arnon, 1949) were analysed.

Results and Discussion

Pharmacognostic study

By screening the various leaf extracts of three test plants, the pharmacognostic features were examined through the following parameters.

Organoleptic study

The investigation of organoleptic study of leaf power of A. indica, V. negundo and C. sativum indicated the characters like colour, odour and taste. The colour of the leaf powder and the taste were observed and the results are shown in Table- 1. The colour varied from dark green to light green in all the three plants with bitter taste and pungent odour.

Table 1: Organoleptic Study of The Powders of  A. Indica, V. Negundo and C. Sativum.

Pandey et al. (1984) and Gupta (1986) treated the plant powders with different chemical reagents and observed their behaviors. Here also the above three plant powders were treated with different chemical reagents to find out their diagnostic features.

Fluorescence Analysis

All the plant powders treated with various chemicals exhibited various colours in the visible and UV light when compared to control, the three leaf powders revealed colour changes from green to brown in 3^rd and 4^th  treatments. When the powders were treated with aqueous 1N NaOH and ethanol all the plants exhibited varied green colours in visible and UV light and the result are depicted in Table- 2.

Table – 2 Fluorescence Analysis of the Powders of A. Indica V. Negundo and C. Sativum.

With the help of fluorescence analysis, we can identify and discriminate Aloe vera, Acorus calamus and Symplocos racemosa from other species. This coincides with the study of Mary et al. (1980) who discriminated two species of Valerina L. on the basis of morphology, fluorescent analysis and microscopic characters.

Behavior of the Leaf powders

It is evident from the results that the leaf powders of three test plants treated with chemicals like FeCl_3, NaOH, H₂O, I₂, HCl, +H₂O, KOH, ethanol, HNO₃ and H₂SO_4, various shades of green, red and brown colours were obtained. The powder as such expressed varied green colours and when it was dissolved in water it showed no change in its colour. Various behaviors of powders with different chemical reagents are depicted in Table- 3.

Table 3: The Behaviour of the Leaf Powders of A. Indica, V. Negundo and C. Sativum When Treated With Different Chemical Reagents.

During a pharmacognostic study carried out on the flower of Pterospermum cicerifolium (L.) by Shome and Mehrotra (1990) greenish purple colour was noted on treatment with 1N HCl and nitro-cellulose.

Phytochemical screening

Phytochemical analysis intends to serve as a major resource for information on analytical and instrumental methodology in plant science (Table – 4). A preliminary study was undertaken to assess the active constituents of A. indica, V. negundo and C. sativum. All the phytochemical tests showed positive results in all the test plants. The phytochemicals screened were cellulose, protein, fat and oil, flavonoids, saponin, steroid, phenol, quinone and tannin. No starch was rated from any of the species of A. indica, V. negundo and C. sativum.

Table 4: Analysis of Phytochemicals Present in  A. Indica V. Negundo and C. Sativum.

The preliminary phytochemical investigation of selected ethno-medicinal plants of Dindigul district showed the presence of phenolics, flavonoids, terpenoids and alkaloids respectively in 60, 58, 50, and 37 plant species (Karuppusamy et al., 2005).

The phytochemical screening of the polyherbal powder showed the presence of alkaloids, carbohydrates, phytosterol and flavonoids. Saponin was absent in all cases. Phytochemicals like alkaloids, carbohydrates, phytosterol, sterols, tannins, proteins, amino acids, saponins, fixed oils, fats and flavonoids were analysed in Solanum xanthocarpum by Udayakumar et al. (2003).

pH

The PH of the leaf extracts of A. indica, V. negundo and C. sativum was estimated and found Maximum as 6.5 in V. negundo. The PH 6 showed the acidic nature of the extracts of A. indica and C. sativum (Table- 5).

Table 5: Ph of Plant Extracts.

Biochemical parameters of test plants

Total Protein Content (Table- 6)

Biochemical studies on the leaf powders of three plants (A. indica, V. negundo and C. sativum) revealed that the protein content in V. negundo has been found to be maximum of 6.08 g per 100 g powder while in A. indica, it has been 3.91 g. In the case of C. sativum the protein content was minimum, 5.12 mg per 100 g. Only slight variation was observed in the values of protein in water and powder extract. Udayakumar et al. (2003) studied the amount of protein present in Solanum xanthocarpum.

Total carbohydrates content

The values obtained for the carbohydrates content of three test plants ranged between 5.02 mg/100 as the minimum in A. indica, 8.32 mg/100g as the maximum in V. negundo and 7.13 mg/100g in C. sativum (Table- 6).

Naseer Banu et al. (2003) estimated carbohydrates contents in Amaranthus viridis and Spinacea oleracea in which, A. viridis showed higher carbohydrate content (3.562 mg/g) than Spinacea oleracea. Amount of carbohydrates in polyherbal powder and various extracts was found to be less when compared with A. viridis.

Phenol Content

There were differences in the values obtained for phenol content of three leaf extracts. A maximum of 5.61mg/100 g phenol was estimated from C. sativum and a minimum of 3.9mg/100 g from A. indica (Table- 6).

Table 6: Estimation of Total Protein, Total Carbohydrates and Phenol.

Amudhan et al. (1999) estimated the total phenol profile in some rice varieties in relation to infestation by Asian rice gall or Seolia oryzae. The amount of phenol in the polyherbal powder (6.09) was greater than the other extracts.

Chlorophyll content

Estimation of chlorophyll in the leaf powder of A. indica showed 0.09 mg of chlorophyll ‘a’, 0.07 mg of chlorophyll ‘b’ and 0.16 mg of ‘total’ chlorophyll per 100 g. While that of V. negundo leaf powder contained 0.12 mg of chlorophyll ‘a’, 0.10 mg of chlorophyll ‘b’ and 0.22 mg of ‘total’ chlorophyll content per 100 g. C. Sativum leaf powder contained 0.08 mg, 0.11 mg and 0.19 mg chlorophyll ‘a’, chlorophyll ‘b’ and ‘total’ chlorophyll respectively. (Table- 7).

Table 7: Estimation Of Chlorophyll.

Sims and Gamon (1999) used spectral reflectance for estimation of chlorophyll, anthocyanin, carotenoid concentration, in which the amount of chlorophyll ‘a’, chlorophyll ‘b’ and total chlorophyll were calculated. Results of the chlorophyll contents of the above mentioned plants were in accordance with the above findings.

Reducing sugar and total soluble sugar content

The amount of reducing sugar present in all the three plants are shown in Table- 8. 100 g of leaf powder of C. sativum showed 4.12 g/100 g reducing sugar, while in V. negundo the presence of reducing sugar has been 3.14 g/100 g. The content of reducing sugar in A. indica has been 1.02 g/100 g.Among the three plants C. sativum leaf powder showed higher content of reducing sugar.

Table 8: Estimation of Reducing Sugar and Total Soluble Sugar.

The amount of total soluble sugar present in 100 g of V. negundo has been 6.9 g while in A. indica the presence of total soluble sugar has been 4.2 g/100 g. The content of total soluble sugar in C. sativum has been 3.2 g/100 g. Among the three plants V. negundo showed higher content of total soluble sugar.

The presence of reducing sugar, resins, etc. was reported by Wahi et al. (1984) in Aganosma dichotoma (Roth). Amount of total soluble sugar present sugar present in extracts and dried powders of A. vera, A. calamus and S. racemosa was observed (Habib et al., 2003).

Conclusions

The results organoleptic study offer a scientific basis for the traditional use of   A. indica, V. negundo and C. sativum which possess characters like varied green, light green, dark green and pungent odour and bitter taste.

The fluorescence studies revealed that the powders of three test plants showed varied degrees of green and brown colours, when it is exposed to visible and UV rays. As the powders were treated with chemicals like FeCl₃. NaOH, KOH, I, HCl, NaOH + H₂O, ethanol, HNO₃ and H₂SO₄, the colour changes were noted in the treated powders and colour varied from green, orange and brown.

The phytochemical screening of the test plants may be attributed to the nature of biological active components. The pH of the test plants were found to be acidic and neutral in nature. Of the powders analyzed, V. negundo leaf powder showed the maximum protein content, carbohydrates, chlorophylls and total soluble sugars. C. sativum exhibited highest phenol and reducing sugar.

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