Iranian Journal of Pharmaceutical Research (2003)  77-82
Received: June 2002
Accepted: May 2003

Several phytochemical surveys have been published, including the random sampling approach which involved some plant accessions collected from all parts of the world. The major chemical substances of interest in these surveys have been the alkaloids and steroidal sapogenins (saponins), however, other diverse groups of naturally occurring phytochemicals such as flavonoids, tannins, unsaturated sterols, triterpenoids, essential oils, etc. have also been reported.

Our approach involved the collection, identification, extraction and phytochemical evaluation of extracts derived primarily from a random selection of commonly occurring native plants. At the time of collection, a pressed specimen was prepared and retained in the Herbarium of the Department of Pharmacognosy, School of Pharmacy, Shaheed Beheshti University of Medical Sciences. Each plant sample was then air-dried and milled to a coarse powder. This article will present the procedures used in preparing the test extracts and the results obtained from the 55 plant successions (2). The results of the chemical screening of fifty five plants, growing in the western region of Iran, are also presented in this paper.

Aerial parts of the plants screened in this investigation were collected from different localities in western Iran (Table 1), during the flowering period, dried in shadow, and then powdered.

Phytochemical screenings were performed as described in previous works. Samples of plant materials were extracted with soxhelet extractor and hydrous methanol. The following methods were applied:

The alcoholic extract (corresponding to 2.5 g of plant material) was evaporated to dryness and the residue was heated on a boiling water bath with 2N HCl (5 ml). After cooling, the mixture was filtered and the filtrate was divided into two equal portions. One portion was treated with a few drops of Mayer's reagent and the other with equal amounts of Wagner's reagent (3). The samples were then observed for the presence of turbidity or precipitation. A (+) score was recorded if the reagent produced only a slight opaqueness; a (++) score was recorded if a definite turbidity, but no flocculation was observed and a (+++) score was recorded if a definite heavy precipitate or flocculation was produced(4).

The alcoholic extract ( 5 ml, corresponding to 1 g of plant material) was treated with a few drops of concentrated HCl and magnesium turnings (0.5 g).The presence of flavonoids was indicative if pink or magenta-red color developed within 3 min (5).

About 2.5 g of the plant material was extracted with boiling water. After cooling, the extract was shaken vigorously to froth and was then allowed to stand for 15-20 min and classified for saponin content as follows: no froth = negative; froth less than 1 cm = weakly positive; froth 1.2 cm high = positive; and froth greater than 2 cm high = strongly positive) (6,7).

The alcoholic extract (corresponding to 1 g of plant material) was evaporated and the residue was extracted by 10 ml of hot 0.9% NaCl solution, filtered and divided into 3 equal portions. A sodium chloride solution was added to one portion of the text extract, 1% gelatin solution to a second portion and the gelatin-salt reagent to a third portion. Precipitation with the latter reagent or with both the second and third reagent is indicative of the presence of tannins. Positive tests are confirmed by the addition of FeCl₃ solution to the extract and should result in a characteristic blue, blue-black, green or blue-green color and precipitate (phenolic compounds) (8, 9).

Table 1 reports the results obtained. Of the investigated plants, 39 were found to be alkaloid bearing, 37 showed the presence of flavonoids, 20 tannins and 44 saponins. The following plant species were found to contain alkaloid and they have not been previously reported in the literature for their alkaloids: Vaccaria pyramidata Medicus, Achillea Bibersteinii Afan, Centaurea virgata Lam. var. squarosa Roth., Bidens tripartita L., Lactuca serriola L., Pulicaria dycenterica (L.) Bernh., Tripleurospermum decipiens (Fisch. & C. A. Mey) Bornm., Cardaria draba (L.) Desv., Nasturtium officinale (L.) R. Br., Rapistrum rugosum L., Sinapis arvensis L. Marrubium vulgare L., Mentha longifolia (L.) hud., Phlomis Olivieri Benth., Prunella vulgaris L., Glycyrriza glabra L. (herb), Trifolium pratense L., Alcea digitata (Boiss.) Alef., Malva neglecta Wallr., Plantago lanceolata L., Polygonum aviculare L., Polygonum persicaria L., Veronica Anagalis-aquatica L., Astrodaucus orientalis (L.) Drude, Chaerophyllum L. sp., Lisaea heterocarpa Boiss., Urtica dioica L., Verbena officinalis L.

The following plants species were found to contain flavonoid and they have not been previously reported in the literature for their flanonoids: Vaccaria pyramidata Medicus, Achillea Bibersteinii Afan, Anthemis leptophyla Eig, Centaurea virgata Lam. var. squarosa Roth, Cichorium intybus L., Lactuca serriola L., Tripleurospermum decipiens (Fisch. & C. A. Mey) Bornm, Cardaria draba (L.) Desv. Convolvulus arvensis L. Marrubium vulgare L., Phlomis Olivieri Benth., Prunella vulgaris L., Alcea digitata (Boiss.) Alef., Malva neglecta Wallr., Plantago lanceolata L., Papaver dubium L., Polygonum aviculare L., Polygonum persicaria L., Rumex crispus L., Chaerophyllum L. sp., and Lisaea heterocarpa Boiss.

The following plant species were found to contain saponin and they have not been previously reported in the literature for their saponin: Anchusa italica Retz., Achillea Bibersteinii Afan, Anthemis leptophyla Eig., Centaurea virgata Lam. var. squarosa Roth., Lactuca serriola L., Pulicaria dycenterica (L.) Bernh., Tripleurospermum decipiens (Fisch. & C. A. Mey) Bornm., Cardaria draba (L.) Desv., Nasturtium officinale (L.) R. Br., Marrubium vulgare L., Phlomis Olivieri Benth., Prunella vulgaris.
(Brunella vulgaris Moench), Trifolium pratense L., Alcea digitata (Boiss.) Alef., Malva neglecta Wallr., Polygonum aviculare L., Polygonum persicaria L., Rumex crispus L., Veronica Anagalis-aquatica L., Astrodaucus orientalis (L.) Drude, Chaerophyllum L. sp., Lisaea heterocarpa Boiss., Urtica dioica L., and Verbena officinalis L.

The following plants species were found to contain tannin and they have not been previously reported in the literature for their tanin: Chenopodium album L., Bidens tripartita L., Pulicaria dycenterica (L.) Bernh., Tripleurospermum decipiens (Fisch. & C. A. Mey) Bornm., Convolvulus arvensis L., Equisetum arvense L., Euphorbia myrsinites L., Mentha longifolia (L.) hud., Melilotus officinalis (L.) Desr., Polygonum aviculare L., Polygonum persicaria L., Rumex crispus L. and Bupleurum rotundifolium L.

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