IntroductionPropolis is a complex resinous substance manufactured by honeybees. It consists of exudates collected from the parts of various plant species, substances secreted from bee metabolism, and materials which are introduced during propolis elaboration. [1][2][3] In general, it is composed of 50% resin and vegetable balsam, 30% wax, 10% essential and aromatic oils, 5% pollen and 5% various other organic substances including debris. Exudates collected from leaves and leaf buds, mucilages, gums, resins and latices contribute the most to the constituents of propolis.2 Of these, the largest group of compounds is the flavonoid pigments, such as luteolin, eriodictyol, galangin and quercetin. Flavonoids are ubiquitous in the plant kingdom, occurring naturally in foods and at concentrations of <0.1-0.7% in propolis.2,4-7 Other non-flavonoid constituents include caffeic acids and their esters (2-20%), such as caffeic acid phenethyl ester (CAPE).

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New petrological and mineral chemical data indicate a clockwise P-T path for medium-to high-grade metamorphic mafic rocks in different thrust sheets of the Tugela Terrane within the Mesoproterozoic Natal Belt in KwaZulu-Natal (eastern South Africa). Three metamorphic stages are distinguished: (i) an early upper amphibolite-to lower granulite-facies metamorphic event (M 1) is indicated by rare relics of clinopyroxene; (ii) mineral chemical and textural equilibration during M 2 at calculated pressure-temperature conditions of 4.5 to 6 kbar and 693 to 750°C; and (iii) partial diffusional resetting of mineral compositions during subsequent uplift and exhumation (M 3) under lower amphibolite-to greenschist-facies conditions. No major differences were noted in the tectonothermal regimes at which each of the respective thrust sheets were deformed suggesting that the Tugela Terrane was a homogenous package and experienced uniform P-T conditions. The new data acquired in this study contribute to an improvement in the ongoing development of a tectono-thermal and geodynamic model for the Natal Belt.