Preliminary Phytochemical Screening of Various Extracts of Punica Granatum Peel, Whole Fruit and Seeds

Introduction

The therapeutic efficacy of many indigenous plants for various diseases has been described by traditional herbal medicinal practitioners.^[1] Natural products are the source of synthetic and traditional herbal medicine.

The pomegranate, Punica granatum, an ancient, mystical, and highly distinctive fruit, is the predominant member of Punicaceae family. The pomegranate tree typically grows 12–16 feet, has many spiny branches. The ripe pomegranate fruit can be up to five inches wide with a deep red, leathery skin, is grenade-shaped, and crowned by the pointed calyx. The fruit contains many seeds (arils) separated by white, membranous pericarp, and each is surrounded by small amounts of tart, red juice. The pomegranate is native from the Himalayas in northern India to Iran but has been cultivated and naturalized since ancient times over the entire Mediterranean region. It is also found in India and more arid regions of Southeast Asia, the East Indies, and tropical Africa.^[2]

The potential therapeutic properties of pomegranate are wide-ranging and include treatment and prevention of cancer, cardiovascular disease, diabetes, dental conditions, and protection from ultraviolet (UV) radiation. Other potential applications include infant brain ischemia, Alzheimer's disease, male infertility, arthritis, and obesity.^[3–7] The potent antioxidant capacity of pomegranate and its components has been reported by numerous scientists using multiple in vitro assay systems. ^[8]

The medicinal importance of a plant is due to the presence of some special substances like alkaloids, glycosides, resins, volatile oils, gums and tannins, etc. The active principles usually remain concentrated in the storage organs of the plants.^[9]

Considering all these facts, the present study was designed to investigate the presence of various phytochemicals in the three different extracts of Punica granatum peel, whole fruit and seeds, a plant which evokes various therapeutic effects.

Materials and Methods

Discussion

The preliminary phytochemical screening tests may be useful in the detection of the bioactive principles and subsequently may lead to the drug discovery and development. Further, these tests facilitate their quantitative estimation and qualitative separation of pharmacologically active chemical compounds. ^[12]

The phytochemical screening in the present study, has revealed the presence of triterpenoids, steroids, glycosides, flavonoids, tannins, carbohydrate and vitamin C in the peel extract; triterpenoids, steroids, glycosides, saponins, alkaloids, flavonoids, tannins, carbohydrate and vitamin C in the whole fruit extract and triterpenoids, steroids, glycosides, saponins, alkaloids, tannins, carbohydrate and vitamin C in the seeds extract. Further the presence of different phytoconstituents in the three different extracts may be responsible for the therapeutic properties of pomegranate.

Flavonoids and tannins are phenolic compounds and plant phenolics are a major group of compounds that act as primary antioxidants or free radical scavengers. Since these compounds were found to be present in the extracts, it might be responsible for the potent antioxidant capacity of pomegranate. The secondary metabolites (phytochemicals) and other chemical constituents of medicinal plants account for their medicinal value. For example, saponins have hypotensive and cardiodepressant properties ^[13]. Glycosides are naturally cardioactive drugs used in the treatment of congestive heart failure and cardiac arrhythmia ^[14]. The presence of saponins in whole fruit and seeds extract and glycosides in all the extracts might play a role in the cardioprotective potential of pomegranate.

Since the whole fruit extract contains the components of both peel and seeds, it was found to contain more constituents. It would thus mean that in this study, the whole fruit extract had the highest number of bioactive compounds. Since the yield of bioactive metabolites in a plant extract also varies considerably with the method/solvent of extraction ^[15,16] it is plausible that the ethanolic extracts were generally more potent than the aqueous extracts probably because the active principles in the plant dissolved more readily in and were better extracted by a less polar solvent (ethanol) than water. This is in agreement with many literatures reporting of differences in the activities of extracts obtained from the same morphological part of a plant using different solvents. For instance, the methanolic extract of the fruits of Tetrapleura tetraptera is more potent than the aqueous extract ^[17]. The preliminary phytochemical tests are helpful in finding chemical constituents in the plant material that may lead to their quantitative estimation and also in locating the source of pharmacologically active chemical compound.

Conclusion

The presence of phytoconstituents make the plant useful for treating different ailments and have a potential of providing useful drugs of human use. In the present study, we have found that most of the biologically active phytochemicals were present in the ethanolic, aqueous and chloroform extracts of Punica granatum peel, whole fruit and seeds. Since the ethanolic extract of whole fruit contains more constituents it can be considered beneficial for further investigation. The medicinal properties of Punica granatum peel, whole fruit and seeds extract may be due to the presence of above mentioned phytochemicals.