Eucalyptus is well represented in different Pharmacopeias for its variant pharmacology and depicts a wide range of photochemicals like triterpenoids, flavonoids, polyphenols, gallotannins and macrocarpals both in its volatile and nonvolatile fractions. Hot aqueous leaf decoctions of` Eucalyptus have been recommended as ‘herbal tea’ in different regions of world for its hypoglycemic potentials. However lack of definitive dosage formulations of Eucalyptus bioactive, side effects like nausea, vomiting, gastric irritation, organoleptic unacceptability have limited its application; besides data on toxicology and posology being inconsistent and variant. In the current research work firstly comparative evaluations of hypoglycemic potentials amongst three Eucalyptus spp. E. globulus, E. citriodora, E. camaldulensis have been done by in vitro a-glucosidase assay. E. globulus showed maximal inhibitory effect in a concentration dependent manner (IC50 = 2.0829 ± 0.001 µg/ml) followed by E. citriodora (IC50 = 2.11117 ± 0.011 µg/ml) and E. camaldulensis (IC50 = 2.68395 ± 0.005 µg/ml). Next, leaf extract concentrate of E. globulus (EGLE) was bio-fabricated to microcapsules by a combined liquid orifice-emulsification-ionic gelation method where active extract is embedded in inner alginate gel matrix with an outer chitosan coating. Mucoadhesivity of the microcapsules were tested on rat intestinal tissues by an in vitro adhesion testing called wash-off test. Microencapsulation efficiency was 97.9 ± 0.001-98.3 ± 0.001% and exhibited good mucoadhesivity in wash-off test. Initial EGLE release was slow but a controlled release of 12-14 hr was achieved in dissolution studies in vitro. Kinetic release data of EGLE fits well with first order and Higuchi Model however there is a predominance of first order release kinetics and the EGLE release pattern was primarily diffusion controlled. Further “n” value of Korsmeyer-Peppas equation showed that mechanisms of EGLE release followed anomalous non-Fickian diffusion and also by erosion. The optimized microcapsules were found to be promising for oral controlled delivery of Eucalyptus extract.
Source: Pharm Drug Deliv Res 3:2