Anthocyanins are colored water-soluble pigments belonging to the phenolic group. The pigments are in glycosylated forms. Anthocyanins responsible for the colors, red, purple, and blue, are in fruits and vegetables. Berries, currants, grapes, and some tropical fruits have high anthocyanins content. Red to purplish blue-colored leafy vegetables, grains, roots, and tubers are the edible vegetables that contain a high level of anthocyanins. Among the anthocyanin pigments, cyanidin-3-glucoside is the major anthocyanin found in most of the plants. The colored anthocyanin pigments have been traditionally used as a natural food colorant. The color and stability of these pigments are influenced by pH, light, temperature, and structure. In acidic condition, anthocyanins appear as red but turn blue when the pH increases. Chromatography has been largely applied in extraction, separation, and quantification of anthocyanins. Besides the use of anthocyanidins and anthocyanins as natural dyes, these colored pigments are potential pharmaceutical ingredients that give various beneficial health effects. Scientific studies, such as cell culture studies, animal models, and human clinical trials, show that anthocyanidins and anthocyanins possess antioxidative and antimicrobial activities, improve visual and neurological health, and protect against various non-communicable diseases. These studies confer the health effects of anthocyanidins and anthocyanins, which are due to their potent antioxidant properties. Different mechanisms and pathways are involved in the protective effects, including free-radical scavenging pathway, cyclooxygenase pathway, mitogen-activated protein kinase pathway, and inflammatory cytokines signaling. Therefore, this review focuses on the role of anthocyanidins and anthocyanins as natural food colorants and their nutraceutical properties for health. Abbreviations: CVD: Cardiovascular disease VEGF: Vascular endothelial growth factor

3 34 4 P roblem-based learning curricula have been introduced in many medical schools around the world.1,2 However, their adoption was met with some concern, primarily because of the substantial manpower needed. For example, student contact hours are 3-4 times greater for educators in a problem-based learning curriculum than for educators in a traditional curriculum. As a consequence, the economic viability of problem-based learning becomes a major concern when class sizes exceed 100 students.3 Given the limited resources available, 4 evidence-based evaluation of the effects of problem-based learning during medical school on improving physician competency would certainly strengthen any justification for the adoption of such programs. 5-9Past reviews of problem-based learning focused only on its effects during medical school or postgraduate training.10-16 In addition, 4 of those reviews also studied student and educator preferences and indicated that medical students 11,14,15 and educators 16 generally prefer problem-based learning to traditional teaching methods. The reviews did not study the effects of problem-based learning during medical school on the competencies of practising physicians. Colliver emphasized this lack of evidence when he cautioned that student satisfaction cannot be extrapolated as a predictor of physician competency.17 To our knowledge, there has been only one systematic review, published in 1993, that indirectly reported the effects of problembased learning during medical school on physician competency after graduation. The study was based on a small sample of doctors in their early postgraduate years.16 Since then, many rigorous studies have evaluated the effects of problem-based learning during medical school up to 20 years after graduation. We performed a systematic review of controlled studies to determine whether problem-based learning during medical school leads to greater physician competencies after graduation. MethodsIn our study, we used Maudsley's definition of problem-based learning, which she defined as both a method and philosophy involving problem-first learning via work in small groups and independent study. The effects of problem-based learning during medical school on physician competency: a systematic review Background: Systematic reviews on the effects of problembased learning have been limited to knowledge competency either during medical school or postgraduate training. We conducted a systematic review of evidence of the effects that problem-based learning during medical school had on physician competencies after graduation.

Fruits and vegetables are colorful pigment-containing food sources. Owing to their nutritional benefits and phytochemicals, they are considered as 'functional food ingredients'. Carotenoids are some of the most vital colored phytochemicals, occurring as all-trans and cis-isomers, and accounting for the brilliant colors of a variety of fruits and vegetables. Carotenoids extensively studied in this regard include β-carotene, lycopene, lutein and zeaxanthin. Coloration of fruits and vegetables depends on their growth maturity, concentration of carotenoid isomers, and food processing methods. This article focuses more on several carotenoids and their isomers present in different fruits and vegetables along with their concentrations. Carotenoids and their geometric isomers also play an important role in protecting cells from oxidation and cellular damages.

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By-products derived from food processing are attractive source for their valuable bioactive components and color pigments. These by-products are useful for development as functional foods, nutraceuticals, food ingredients, additives, and also as cosmetic products. Lycopene is a bioactive red colored pigment naturally occurring in plants. Industrial by-products obtained from the plants are the good sources of lycopene. Interest in lycopene is increasing due to increasing evidence proving its preventive properties toward numerous diseases. In vitro, in vivo and ex vivo studies have demonstrated that lycopene-rich foods are inversely associated to diseases such as cancers, cardiovascular diseases, diabetes, and others. This paper also reviews the properties, absorption, transportation, and distribution of lycopene and its by-products in human body. The mechanism of action and interaction of lycopene with other bioactive compounds are also discussed, because these are the crucial features for beneficial role of lycopene. However, information on the effect of food processing on lycopene stability and availability was discussed for better understanding of its characteristics.

Strong support from the academic administrators (dean and other staff responsible for implementation of the curriculum) in the introduction of PBL into the curriculum and careful training of both faculty and students appear to be key factors to ensure the successful implementation of PBL in Asian medical schools.

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SummaryThe nutritional factors which affect lead absorption have been studied. Synthetic diets of known composition were compounded to contain 0-075% Pb as PbCl2 labelled with 203Pb. Rats were exposed to lead for periods of 48 hr. The dietary intake was then measured and the absorption of lead determined by means of a whole-body counter. Lead absorption was increased by high fat, low mineral, low protein and high protein diets but was decreased by high mineral diet. Low fat, low fibre, high fibre, low vitamin and high vitamin diets had no effects on lead absorption.