Traditional uses, phytochemistry and pharmacology of Ficus religiosa: A review

Abstract

Ethnopharmacological relevance

Ficus religiosa L. (Moraceae) has been extensively used in traditional medicine for a wide range of ailments of the central nervous system, endocrine system, gastrointestinal tract, reproductive system, respiratory system and infectious disorders.

Aim of the review

To comprehend the fragmented information available on the botany, traditional uses, phytochemistry, pharmacology and toxicology of F. religiosa to explore its therapeutic potential and future research opportunities.

Materials and methods

All the available information on F. religiosa was collected via electronic search (using Pubmed, SciFinder, Scirus, Google Scholar, Agricola and Web of Science) and a library search.

Results

Ethnomedical uses of F. religiosa are recorded throughout South Asia, where it has been used for about 50 types of disorders. Phytochemical research had led to the isolation of phytosterols, amino acids, furanocoumarins, phenolic components, hydrocarbons, aliphatic alcohols, volatile components and few other classes of secondary metabolites from F. religiosa. Fresh plant materials, crude extracts and isolated components of F. religiosa showed a wide spectrum of in vitro and in vivo pharmacological activities like, antidiabetic, cognitive enhancer, wound healing, anticonvulsant, anti-inflammatory, analgesic, antimicrobial, antiviral, hypolipidemic, antioxidant, immunomodulatory, antiasthmatic, parasympathetic modulatory, esterogenic, antitumor, antiulcer, antianxiety, antihelmintic, endotheilin receptor antagonistic, apoptosis inducer and hypotensive.

Conclusions

F. religiosa emerged as a good source of traditional medicine for the treatment of asthma, diabetes, diarrhea, epilepsy, gastric problems, inflammatory disorders, infectious disorders and sexual disorders. Although many of the experimental studies validated its traditional medicinal uses, but employed uncharacterized crude extracts. Thus, it is difficult to reproduce the results and pinpoint the bioactive metabolite. Hence, there is a need of phytochemical standardization and bioactivity-guided identification of bioactive metabolites. The results of few pharmacological studies and bioactive metabolites already reported in F. religiosa warrant detailed investigation for its potential against cancer, cardiovascular disorders, neuroinflammatory disorders, neuropsychiatric disorders, oxidative stress related disorders and parasitic infections. The outcome of these studies will further expand the existing therapeutic potential of F. religiosa and provide a convincing support to its future clinical use in modern medicine.

Introduction

The genus Ficus (Moraceae) constitute one of the largest genera of angiosperms with more than 800 species of trees, epiphytes and shrubs in the tropical and sub-tropical regions worldwide. It is one of the most diverse plant genera in regard to its growth habit with both deciduous and evergreen free-standing trees, stranglers, climbers, creepers, small shrubs, lithophytes and rheophytes (Loutfy et al., 2005, Ronsted et al., 2008). The Asian–Australasian region is the richest and most diverse containing about 500 Ficus species. In contrast, the richness of Ficus in Africa and the Neotropics is lower, with approximately 110 and 130 species, respectively. About half of the Ficus species are monoecious and the rest are functionally dioecious (Berg, 2003). All members of the genus Ficus share the distinctive fig inflorescence (syconium), which is the site of an obligate mutualism with pollinating fig wasps of the family Agaonidae (Ronsted et al., 2008).

Ficus religiosa L. is the most popular member of the genus Ficus, and is known by more than 150 names (Appendix A). It is native of the sub-Himalayan tract, Bengal and central India. It has been extensively distributed worldwide through cultivation (McFarland, 1944, Galil, 1984). F. religiosa tree begin its life epiphytically and then strangle the host by its far-growing roots that extend to the ground, establishing it as an independent tree. It is found in the areas up to 1500 m elevation having an annual rainfall varying from 50 to 500 cm during the monsoon season and tolerates a wide variation in temperature (below 0 °C and above 40 °C) (Pullaiah, 2006). It is the most sacred tree of South Asia, to both Hindus and Buddhists. The specific epithet “religiosa” and synonym “bodhi tree” alludes to the religious significance attached to this tree (Kala et al., 2006, Sitaramam et al., 2009). Since antiquity, F. religiosa has got mythological, religious and medicinal importance in Indian culture. It is the oldest portrayed tree in India. Atharvaveda (sacred text of Hinduism) links it with the third heaven and discusses its medicinal properties along with Soma and Kustha (holy medicinal herbs). References to F. religiosa are found in several ancient holy texts like, Arthasastra, Puranas, Upanisads, Ramayana, Mahabharata, Bhagavadgita, Buddhistic literature, etc. (Prasad et al., 2006). The therapeutic utilities of F. religiosa have been indicated in traditional systems of medicine like, Ayurveda, Unani, etc. It has been used to cure the disorders of the central nervous system (epilepsy, migraine, etc.), endocrine system (diabetes, etc.), gastrointestinal tract (vomiting, ulcers, stomatitis, constipation, liver diseases, etc.), reproductive system (menstrual irregularities, etc.), respiratory system (asthma, cough, etc.) and infectious diseases (chickenpox, elephantiasis, leprosy, tuberculosis, gonorrhea, scabies, etc.). Continuous research is in progress to validate its traditional medicinal uses, which is described in detail in the present review.

F. religiosa is a large deciduous tree up to 35 m in height (Fig. 1A), epiphytic when young, and crown wide when mature. Its dropping branches bear coriaceous, stipulate leaves that are dark green in color (Fig. 1B), 10–18 × 7.5–10 cm, ovate-rotund, narrow upward and the apex produces into a linear-lanceolate tail about half of the main portion of the blade, base broadly cuneate to cordate, margin entire or undulate; secondary veins five to seven on each side of the midvein, lateral veins eight pair with finely reticulate venation (Fig. 1C); petioles 7.5–10 cm long, slender; stipules minute ovate, acute. Figs (Fig. 1D) axillary on leafy branchlets, paired or solitary, red when mature (Fig. 1E), globose to depressed globose, 1–1.5 cm in diameter, smooth; peduncle 4–5 mm; involucral bracts ovate. Male, gall (sterile female) and female flowers occur within the same fig. Male flowers: few, near apical pore, sessile; calyx 2–3-lobed, margin revolute; stamen 1; filament short. Gall flowers: pedicellate; calyx 3–4-lobed; ovary globose, smooth; style short; stigma enlarged, 2-lobed. Female flowers: sessile; calyx 4-lobed, broadly lanceolate; ovary globose, smooth; style thin; stigma narrow (Kirtikar and Basu, 1993, Warrier et al., 1995, Zhekun and Gilbert, 2003). As all the Ficus species are pollinated by a species specific wasp, the pollinator wasp of F. religiosa is Blastophaga quadraticeps (Galil, 1984).

The bark (Fig. 1F) is flat or slightly curved with thin or membranous flakes, often covered with crustose lichen patches. The outer bark is grayish or ash-colored, exfoliated with irregular rounded flakes of 2–2.5 cm thickness. The middle bark sections appear as brownish or light reddish brown in color. The inner part consists of the layers of light yellowish or orange brown colored granular tissue. The bark is odorless and its taste is astringent. The plant bears few adventitious roots (Fig. 1G) (Warrier et al., 1995, Ali, 2007, Koilpillai et al., 2010).

F. religiosa is widely cultivated as a street or park tree in tropical and sub-tropical countries worldwide, especially in the vicinity of the temples. It can be propagated by seeds or by vegetative methods. Seeds are sown in the raised bed in March–July. Germination starts within a week and lasts for about 1 month. Seedlings are maintained in the nursery for 1 year, and then planted out in June–July, with the onset of monsoon. The plants are irrigated at regular intervals and prevented from the weeds by timely weeding.

F. religiosa can also be propagated by semi-hardwood cuttings of straight, well grown branches, measuring 2 m in length and about 5 cm in diameter. Branch cuttings are treated with auxins before planting in 0.5 m deep pits prepared with well rotten compost and soil. Planting is done with the commencement of monsoon in July. Root initiation occurs within 1 month of the plantation (Galil, 1984, Williamson and Hooper, 2002, Pullaiah, 2006).

Recently, an in vitro culture technique has been described for the mass propagation of F. religiosa using apical and axillary buds of young sprouts (Hassan et al., 2009). However this technique still remains as an experimental procedure, more studies are required to commercialize it.