A review on Sterculia urens Roxb.: a boon to the livelihood for tribal people and industry

Bioremediation of mercury (II) from aqueous solution by gum karaya ( Sterculia urens): A natural hydrocolloid

Gum karaya is a polysaccharide gum from Sterculia urens tree. It is used as an emulsifier and thickening agent in cosmetics and pharmaceuticals. However, it has very strong swelling properties, high viscosity, and low solubility, providing the restricted applications in the food industry. The main objective of this study was to investigate the effects of different heat treatment and microwave variables (i.e., time: 8, 10, and 12 min; power: 700 and 1000 W) on the functional properties of gum karaya in the aqueous system and oil-in-water emulsion. In this regard, the rheological properties, emulsifying activity, average droplet size, and surface morphology of the native- and microwave-treated gums were analyzed and compared. Dynamic oscillatory test indicated that the microwave-treated gum karaya had more gel-like behavior than viscous-like behavior (G′ > G″) at a relatively high concentration (20% or 20 g/100 g). When gum karaya was treated by microwave for 8–12 min, both elastic (G′) and viscous (G″) moduli were declined. The native- and microwave-treated gum karaya exhibited a shear-thinning (pseudoplastic) behavior in the aqueous system and oil-in-water emulsion. The results showed that the microwave-treated gum karaya had smaller particles than the native gum in the aqueous system. On the other hand, the emulsion containing the microwave-treated gum karaya had finer emulsion droplets than the control containing the native gum karaya. This confirmed that the application of microwave treatment led to significantly (p < 0.05) improve the emulsifying activity of gum karaya.

Kullu or gum karaya (Sterculia urens) is a gum-yielding tree found in the dry deciduous forests of Madhya Pradesh, India. The tree is source of an important gum called kullu gum, gum karaya or katira. Katira—a nationalized forest product in Madhya Pradesh—is commercially and industrially very important. The Saheriyas—a forest dependent tribal community of Sheopur—extract katira from naturally growing kullu trees in the neighbouring forests, using their traditional gum tapping technique. However, this method of gum tapping is destructive and wasteful. Also, the gum thus collected contains impurities like wood-chips and dust and fetches a very low market price. Recognising the need to enhance the capacities of the gum tappers in the District to harvest this precious NTFP resource sustainably, the Indian Institute of Forest Management (IIFM) conducted action research and organised a series of village-level skill enhancement programs in Sheopur for the gum-tappers as well as for the Forest Department staff. This paper discusses the improved method of gum tapping that has been disseminated among the tribal community in Sheopur. Adoption of this technique will help to conserve the locally available Kullu resource and provide long term livelihood support for the community.

Papad is an indigenous savory food item found in most Indian homes. It is commonly made with black gram (Phaseolus mungo) flour. The composition of the papad varies by addition of a large number of ingredients such as cereal flour, pulse flour, soya flour, spice mixes, chemical mixes and different vegetable juices to improve both organoleptic and nutritional characteristics. Diametrical expansion is one of the desirable sensory attributes during frying of papads. The present work was taken up to study the effect of incorporation of various ingredients namely nalleru (Cissus quadrangularis), gum karaya(Sterculia urens ) and soya flour on diametrical expansion and oil absorption of papads. Papads of 10 cm diameters were deep fat fried at 185 ± 5C after different storage periods up to 60 days. It was observed that the diametrical expansion and oil absorption did not show any major changes with the addition of Cissus extract. The addition of soya flour reduced the oil absorption. Gum karaya helped in retaining the dough’s moisture, which in turn resulted in increased diametrical expansion on deep fat frying.

This paper illustrates a method for the stabilization of nanoscale zerovalent iron (NZVI) suspensions with a “green” biopolymer, Gum Karaya (GK).

Sterculia gum is one of the medicinally important plant-derived water soluble polysaccharides obtained from the exudate of the tree, Sterculia urens (Family: sterculiaceae). It is recognized as a promising biodegradable material in the development of various biomedical applications including drug delivery applications, wound dressing applications, etc. Sterculia gum is also employed as excipient in the designing of various pharmaceutical applications. In recent years, several attempts for the modification of sterculia gum have been undertaken to develop sterculia gum-based hydrogels for controlling the rate of hydration and swelling, and also tailoring the release profile of various types of drugs. In the development of these sterculia gum-based hydrogels, modifications of sterculia gum through polymer blending, cross-linking, interpenetrated polymer network (IPN) formation, polymer grafting, etc., were investigated for improved drug delivery applications. Most of these already reported sterculia gum-based hydrogels were found effective for gastroretentive deliveries as wound dressings for sustained release of various drugs. The current chapter deals with a comprehensive and useful discussion on already investigated sterculia gum-based hydrogels for the use in drug delivery applications, where the first portion of the chapter contains source, composition, and properties of sterculia gum and the latter portion contains discussion on the formulations of various sterculia gum-based hydrogel systems used for various types of drug delivery applications.

Ocular inserts of Pilocarpine nitrate (PN) were prepared using modified karaya gum (MKG) alone as release retarding polymer and in combination with the copolymer sodium alginate. Modification of the karaya gum was done by treating it with the trisodium trimetaphosphate (STMP) by cross linking method and evaluated for its physicochemical properties. Films of the MKG were prepared by employing solvent casting method using varying concentrations (600mg, 500mg and 400mg) of MKG and the sandwiching technique was used for the loading of drug. Sodium alginate (SA) and PN blend were prepared by triturating their appropriate amounts. Six ocusert formulations (F1-F6) were prepared with different concentrations of the polymer i.e MKG and SA while the amount of PN was kept constant in formulations. Formulations F1-F3 contained the MKG alone in varying concentrations (600mg, 500mg and 400mg) and F4-F6 contained SA (0.5 mg) in addition to MKG. The surface pH of prepared ocuserts from the formulations (F1-F6) was in the range of 6.63 to 6.8. Thickness range of the ocuserts was from 0.21 to 0.32 mm. Dissolution profiles of prepared ocuserts were studied and drug release was found within the range of 69.2± 1.36 % (F4, minimum) to 90.5± 3.21% (F3, maximum). Overall results of the study concluded that ocuserts fabricated with MKG and SA at optimized concentrations have the potential to sustain the release of PN and therefore reducing dosing frequency and adverse effects.

The gum-yielding species Sterculia urens Roxb., known for its valuable ‘Karaya Gum,’ plays a crucial role in various industries. However, unscientific exploitation, poor natural regeneration and inadequate seedling recruitment have led to a significant decline in its natural populations. A pilot study was conducted across ten sites in different forest divisions of Madhya Pradesh to assess the natural regeneration status. Study revealed that overall natural regeneration status was poor. Based on field observations, the study recommends the inclusion of S. urens in plantation programs of State Forest Departments to enhance its long-term security. Additionally, we advocate for assisted natural regeneration (ANR) activities within its natural ranges, emphasizing monitoring and adaptive management to ensure successful regeneration.

Recent advances of Sterculia gums uses in drug delivery systems

Structure-property relationships in Sterculia urens/polyvinyl alcohol electrospun composite nanofibres.

Ex situ Conservation Using In vitro Methods of an Endangered Plant Sterculia urens Roxb.: A High Volume Trade Plant for Gum Karaya

Chemical and functional characterization of Gum karaya ( Sterculia urens L.) seed meal

Microwave drying and grinding characteristics of gum karaya ( Sterculia urens)

Comprehensive studies were carried out on phenology, floral sexuality, pollination biology, pollen-pistil interaction, breeding system and fruit and seed set on three populations of gum karaya tree (Sterculia urens). The species is andromonoecious and produces a large number of male and a limited number of “bisexual” (functionally female) flowers. The numbers of male and “bisexual” flowers varies not only between trees but also during the flowering period within a tree. Each male flower produces about 5000 fertile pollen grains. Neither in morphology nor in number, is there any difference between pollen grains in the “bisexual” and male flowers. However, pollen grains of “bisexual” flowers are completely sterile and incapable of siring any seeds. Their anthers, however, serve to attract pollinators; the emasculated “bisexual” flowers fail to do so. Thus S. urens is apparently andromonoecious but exhibits cryptic monoecy. That the species is self-incompatible was confirmed by controlled pollinations. The self-incompatibility is of the late-acting type and manifests after the entry of the pollen tube into the ovule. Apis indica is the only pollinator recorded by us and wind plays no role in pollination. The efficacy of pollination is low as only 56% of flowers were estimated to be pollinated. The pollen load on one-third the number of pollinated stigmas was lower than the number of ovules present. Fruit set under open pollination is poor and is highly variable from tree to tree (0.7−3.2%). Apart from pollination constraint, limited resource availability may also contribute to low fruit set.

Realizing the historical importance of central Indian forests in terms of ecological, social and economical perspectives and the present socio-economic changes in the community due to several reasons, the present study was conducted. It aimed at addressing the status of harvesting pattern and supply chain structure of various ethno-botanical species by the tribal communities in the Pachmarhi Biosphere Reserve of India. The questionnaire surveys were conducted in the villages of buffer zone areas of the Pachmarhi Biosphere Reserve and market places for studying the trends and status of collection, seasons of collection, prices, and supply chain of ethnobotanicals. A total 14 ethno-botanical species were found in active trade, and in majority of cases their gum, fruit and seed were collected. The gum yielding species such as <i>Acacia nilotica, Anogeissus latifolia, Sterculia urens, Terminalia tomentosa and Terminalia arjuna</i> were found to be highly paid species among all traded ethno-botanical species. The trade in ethnobotanicals and market trends seemed quite lucrative to the tribal communities and hence they have started unsustainable harvesting of tradable forest resources to get maximum returns unlike their ancestors. Of the total tradable ethnobotanical species 8 species have qualified to various threat categories of IUCN Red List. The results of this study are further discussed in view of the conservation and management of ethnobotanical species.