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International Journal of Phytomedicine and Phytotherapy

Table 1 Preliminary phytochemical tests for plant extracts

From: Correlative study of heavy metal content with biological importance of Solanum virginianum leaf extract

S.N. Metabolites Test Validation
1 Alkaloid 2 ml of extract + 2 ml of 2 N HCl + 2 drops of Wagner’s reagent
2 ml of extract + 2 ml of 2 N HCl + 2 drops of Mayer’s reagent
Reddish-brown precipitation validates the presence of alkaloid
Gelatinous white precipitation validates the presence of alkaloid
2 Tanins and phenol 2 ml of extract + 2 ml water + 2–3 drops of 5% FeCl3 Green precipitate validates the presence of tannin. Purple solution validates presence of phenol.
3 Flavonoid 3 ml of extract + evaporated to dryness. Residue + 1–2 ml 50% CH3CH2OH, heat + 4–5 drops HCl + Mg ribbon Red or orange color validates the presence of flavonoid.
4 Steroid (Salkowski Test) 2 ml extract + 2 ml CHCl3 + 3 ml conc. H2SO4 The reddish brown precipitate validates the presence of steroid.
5 Glycoside 2 ml extract + 2 ml CHCl3 + 1–2 ml CH3COOH Formation of violet or blue to green coloration validates presence of glycoside.
6 Saponin 2 ml extract + evaporated to dryness. Residue + 1 ml water + shaken vigorously. The persistent foam (1 cm in the test tube) validates the presence of saponin.
7 Emodol 2 ml extract + 1–2 ml 25% NH3 + Shaken. A cherries red color indicates the presence of emodol
8 Coumarin 2 ml extract + 3 ml (10%) NaOH Yellow coloration validates presence of coumarin.
9 Anthocyanin 2 ml extract + 2 ml (2 N) HCl + 1 ml NH3 Formation of pinkish red to bluish violet coloration validates presence of the anthocyanin.
10 Protein 2 ml extract + 1 ml (40%) NaOH + 1–2 drops 1% CuSO4 solution. Formation of violet color validates presence of protein.
11 Carbohydrate Fehling’s test: 1 ml extract + 2 ml water + 1 ml Fehling solution (1 and 2) + heated in a water bath
Molisch’s test: 1 ml extract + 5 ml distilled water + 2 drops alcoholic α-naphthol
A brick red precipitate validates presence of reducing sugar.
violet ring at the junction validate the presence of carbohydrates
12 Terpenoids 2 ml extract + 2 ml CHCl3 + 5 ml conc. H2SO4 Reddish-brown coloration validates the presence of terpenoids
13 Glucoside 2 ml extract + few drops conc. H2SO4 black coloration validates the presence of glucoside