Further analyses on Micronesian banana, taro, breadfruit and other foods for provitamin A carotenoids and minerals

Few Micronesian foods have been analyzed for nutrient content. Information is needed on locally grown, culturally acceptable foods that could be promoted to alleviate, vitamin A deficiency in the Federated States of Micronesia. Using an ethnographic approach that included key informant interviews and observation, Micronesian cultivars with potential for high-carotenoid content according to their coloration were identified. These cultivars of banana, giant swamp taro, breadfruit and other foods were analyzed for alpha- and beta-carotene using high-performance liquid chromatography (HPLC) and for nine minerals using inductively coupled plasma (ICP). A wide range of provitamin A carotenoid levels was found in banana, taro, and breadfruit cultivars, some containing very high levels (beta-carotene content from 515 to 6360 mug/100 g in banana, 260 to 1651 mug/100 g in taro, and 295 to 868 mug/100 g in breadfruit, edible portion). Other cultivars contained moderate levels, but as they can be eaten in large quantities, they may contribute significantly to vitamin A status. The taro samples contained very high levels of zinc (mean 5.9 mg/100 g) and significant levels of other minerals (mean content of calcium was 120 mg/100 g). These staples with cultural acceptability and high availability potentially could play a role in vitamin A, micronutrient, and chronic disease programs in the Pacific. (C) 2003 Elsevier Science Ltd. All rights reserved.

Pacific pandanus fruit: an ethnographic approach to understanding an overlooked source of provitamin A carotenoids

Commonly recommended plant sources of provitamin A, such as dark green leafy vegetables, are not acceptable in many population groups. The objective of this study was to identify other indigenous foods that may be effectively promoted to alleviate vitamin A deficiency (VAD) and to gather information relevant to identification, production, acquisition, and consumption of foods relevant to a food-based VAD prevention strategy in the Federated States of Micronesia. An ethnographic study on edible pandanus cultivars, involving key informant interviews and observation was carried out. Analyses revealed a great range in carotenoid content. Several orange-coloured pandanus cultivars, all highly acceptable, contained high levels of carotenoid, almost meeting daily requirements in usual consumption patterns, whereas light yellow-coloured cultivars contained low levels. Availability has decreased substantially in recent years due to increased consumption of imported foods and general neglect of indigenous foods. High-carotenoid pandanus should be promoted for general enjoyment and health benefits.

Molecular characterisation and carotenoid quantification of pro-vitamin A biofortified genetically modified bananas in Uganda

In Uganda, a significant proportion of the population depends on the micronutrient poor East African highland banana as a food staple. Consequently, micronutrient deficiencies such as vitamin A deficiency are an important health concern in the country. To reach most vulnerable rural poor populations, staple crops can be biofortified with essential micronutrients though conventional breeding or genetic engineering. This thesis provided proof of concept that genetically modified East African highland bananas with enhanced provitamin A levels can be generated and fully characterised in Uganda. In addition, provitamin A levels present in popular banana varieties was documented.

Carotenoid content and flesh color of selected banana cultivars growing in Australia.

Background: The problems of vitamin A deficiency and chronic diseases have emerged in recent years in some countries in the Micronesian region. These problems are associated with the dietary shift towards imported processed foods and lifestyle changes. Research in the Federated States of Micronesia indicates that yellow- and orange-fleshed banana cultivars contain significant levels of provitamin A carotenoids. Objective: To identify further banana cultivars that may be promoted to alleviate vitamin A deficiency among children and women and chronic disease problems among adults. Methods: Ripe fruit of banana cultivars growing in Australia (sourced mostly from a field research collection) were assessed for carotenoid content and flesh color. Ten cultivars with yellow or yellow/orange flesh color (including common cultivars of Southeast Asia and the Pacific Islands) were selected and compared with two cream-fleshed cultivars, including Williams, of the Cavendish group, the most commonly marketed banana worldwide. Carotenoid content was analyzed by high-performance liquid chromatography (HPLC). Flesh color was analyzed by HunterLab colorimetry. Results: The yellow/orange-fleshed Asupina (a Fe'i banana) contained the highest level (1,412 μg/100 g) of trans β-carotene, the most important provitamin A carotenoid, a level more than 20 times higher than that of Williams. All 10 yellow or yellow/orange-fleshed cultivars (Asupina, Kirkirnan, Pisang Raja, Horn Plantain, Pacific Plantain, Kluai Khai Bonng, Wain, Red Dacca, Lakatan, and Sucrier) had significant carotenoid levels, potentially meeting half or all of the estimated vitamin A requirements for a nonpregnant, nonlactating adult woman within normal consumption patterns. All were acceptable for taste and other attributes. The cream-fleshed cultivars had minimal carotenoid levels. There was a positive significant correlation between carotenoid content and deeper yellow/orange coloration indicators. Conclusions: These yellow- or yellow/orange-fleshed carotenoid-rich banana cultivars should be considered for promotion in order to alleviate vitamin A deficiency and chronic disease in susceptible target communities and to provide variety and enjoyment as exotic fruits in both developing and industrialized countries.

Chronic alcohol intake upregulates hepatic expression of carotenoid cleavage enzymes and PPAR in rats

Excessive and chronic alcohol intake leads to a lower hepatic vitamin A status by interfering with vitamin A metabolism. Dietary provitamin A carotenoids can be converted into vitamin A mainly by carotenoid 15,15′-monooxygenase 1 (CMO1) and, to a lesser degree, carotenoid 9′10′-monooxygenase 2 (CMO2). CMO1 has been shown to be regulated by several transcription factors, such as the PPAR, retinoid X receptor, and thyroid receptor (TR). The regulation of CMO2 has yet to be identified. The impact of chronic alcohol intake on hepatic expressions of CMO1 and CMO2 and their related transcription factors are unknown. In this study, Fischer 344 rats were pair-fed either a liquid ethanol Lieber-DeCarli diet (n = 10) or a control diet (n = 10) for 11 wk. Hepatic retinoid concentration and expressions of CMO1, CMO2, PPARγ, PPARα, and TRβ as well as plasma thyroid hormones levels were analyzed. We observed that administering alcohol decreased hepatic retinoid levels but increased mRNA concentrations of CMO1, CMO2, PPARγ, PPARα, and TRβ and upregulated protein levels of CMO2, PPARγ, and PPARα. There was a positive correlation of PPARγ with CMO1(r = 0.89; P<0.0001) and both PPARγ and PPARα with CMO2 (r = 0.72, P< 0.001 and r = 0.62, P< 0.01, respectively). Plasma thyroid hormone concentrations did not differ between the control rats and alcohol-fed rats. This study suggests that chronic alcohol intake significantly upregulates hepatic expression of CMO1 and, to a much lesser extent, CMO2. This process may be due to alcohol-induced PPARγ expression and lower vitamin A status in the liver. © 2010 American Society for Nutrition.

Associação entre os polimorfismos do gene BCMO1 (β-caroteno 15,15'-monooxigenase 1) e as concentrações séricas de β-caroteno e retinol em diferentes etnias brasileiras

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Entschlüsselung des Carotinoid-Metabolismus im marinen Schwamm Suberites domuncula

Die Enzyme des Carotinoidstoffwechsels spalten Provitamin A-Carotinoide in wichtige Retinoide (z.B. Vitamin A, Retinsäure), die Organismen während der Entwicklung und in visuellen Systemen benötigen. Die vorliegende Arbeit präsentiert erstmalig eine Carotinoxygenase (BCO) aus Schwämmen (S. domuncula), die einzigartig im Tierreich ist und nur einen orthologen Vertreter in Pflanzen (Crocus sativus) wieder findet. Das Enzym ist eine 7,8(7’,8’)-Carotinoxygenase, die C40-Carotinoide zu einem C10-Apocarotinoid und 8’-Apocarotinal spaltet. Mittels HPLC wurden sowohl die Primärspaltprodukte von β-Carotin, Lykopin und Zeaxanthin als auch das für alle identische innere Kettenstück (Crocetin) bei Doppelspaltung nachgewiesen. Der Nachweis der BCO-Transkripte (unter anderem in-situ) belegt eine Beteiligung des Enzyms während Entwicklungsprozessen und offenbart sowohl eine streng räumlich-zeitliche als auch eine über Rückkopplungsprozesse gesteuerte Regulierung des Enzyms. Ein weiteres hier identifiziertes Gen ähnelt einer bakteriellen Apocarotinoidoxygenase (ACO), welche das 8’-Apocarotinal der BCO erneut spaltet und so Retinal generiert. Letzteres dient als Chromophor zahlreicher visueller Systeme und kann über Enzyme des Retinoidstoffwechsels entweder gespeichert, oder in das wichtige Morphogen Retinsäure umgesetzt werden. Hier werden zwei potentielle Enzyme vorgestellt, die an dieser Interkonversion Retinal/Retinol (Speicher) beteiligt sein könnten als auch eines, das evtl. Retinal zu Retinsäure umsetzt. Die hier vorgestellten Ergebnisse unterstützen die Hypothese, dass Retinsäure kein autapomorphes Morphogen der Chordaten darstellt.

Vitamin A intake and factors influencing it amongst children and caretakers in Kosrae, Micronesia

A cross-sectional study was undertaken in Kosrae, Federated States of Micronesia to assess preschool children and caretaker dietary intake of vitamin A (VA) (including provitamin A carotenoids) and other nutrients contributing to VA status and to investigate relationships between VA intake and factors affecting dietary intake. Ethnography, food sample analysis, two dietary assessment methods (7-day food frequency questionnaire and quantitative 24-hour recall for three nonconsecutive days) administered by trained interviewers to a random sample group, and cultivar difference specification (yellow-fleshed versus white-fleshed bananas) contributed to the richness of the study. Vitamin A intake was low, approximately half of the estimated requirements for children (n = 65) and caretakers (n = 65), whereas protein intake was high. There were no clear significant relationships associated with gender, caretaker education, caretaker occupation, and socio-economic status with VA intake, indicating that a broad-based intervention over all population segments is needed to change dietary behavior, The ethnographic approach was critical for survey instrument development and data analysis.

Carotenoid content of pandanus fruit cultivars and other foods of the Republic of Kiribati

Background: Kiribati, a remote atoll island country of the Pacific, has serious problems of vitamin A deficiency (VAD). Thus, it is important to identify locally grown acceptable foods that might be promoted to alleviate this problem. Pandanus fruit (Pandanus tectorius) is a well-liked indigenous Kiribati food with many cultivars that have orange/yellow flesh, indicative of carotenoid content. Few have been previously analysed. Aim: This study was conducted to identify cultivars of pandanus and other foods that could be promoted to alleviate VAD in Kiribati. Method: Ethnography was used to select foods and assess acceptability factors. Pandanus and other foods were analysed for beta- and alpha-carotene, beta-cryptoxanthin, lutein, zeaxanthin, lycopene and total carotenoids using high-performance liquid chromatography. Results: Of the nine pandanus cultivars investigated there was a great range of provitamin A carotenoid levels (from 62 to 19 086 mu g beta-carotene/100 g), generally with higher levels in those more deeply coloured. Seven pandanus cultivars, one giant swamp taro (Cyrtosperma chamissonis) cultivar and native fig (Ficus tinctoria) had significant provitamin A carotenoid content, meeting all or half of estimated daily vitamin A requirements within normal consumption patterns. Analyses in different laboratories confirmed high carotenoid levels in pandanus but showed that there are still questions as to how high the levels might be, owing to variation arising from different handling/preparation/analytical techniques. Conclusions: These carotenoid-rich acceptable foods should be promoted for alleviating VAD in Kiribati and possibly other Pacific contexts where these foods are important. Further research in the Pacific is needed to identify additional indigenous foods with potential health benefits.

Micronesian banana, taro, and other foods: newly recognized sources of provitamin A and other carotenoids

Vitamin A deficiency (VAD) and chronic diseases are serious problems in the Federated States of Micronesia and other Pacific island countries. Nutrition education programs to address these in Micronesia have had limited success, partly due to lack of information on nutrient content in local foods. The study objective was to identify local plant foods rich in provitamin A and other carotenoids that have high levels of cultural acceptability. Food cultivars likely to be carotenoid-rich (suggested by coloration) were identified using an ethnographic approach including key informant interviews. Raw and cooked samples (mostly cultivars previously not analyzed) of 12 banana, 13 giant swamp taro, 10 breadfruit cultivars and four other local foods were analyzed by high-performance liquid chromatography. Many banana and taro cultivars were found with significant levels of beta- and alpha-carotene; the beta-carotene levels ranged from 30 to 2780 mug/100 g (banana) and. 50 to 2040 mug/100 g (taro). The results highlight the potential significance of cultivar differences in human nutrition, important for evaluation of the diet, establishment of locally relevant dietary guidelines, and research on the relationship between diet, health, and disease. These highly acceptable food cultivars could play an important role in VAD and chronic disease prevention programs in the Pacific. (C) 2003 Elsevier Science Ltd. All rights reserved.

Defining the role of phytoene synthase in carotenoid accumulation of high provitamin A bananas

Vitamin A deficiency (VAD) is a serious problem in developing countries, affecting approximately 127 million children of preschool age and 7.2 million pregnant women each year. However, this deficiency is readily treated and prevented through adequate nutrition. This can potentially be achieved through genetically engineered biofortification of staple food crops to enhance provitamin A (pVA) carotenoid content. Bananas are the fourth most important food crop with an annual production of 100 million tonnes and are widely consumed in areas affected by VAD. However, the fruit pVA content of most widely consumed banana cultivars is low (~ 0.2 to 0.5 ìg/g dry weight). This includes cultivars such as the East African highland banana (EAHB), the staple crop in countries such as Uganda, where annual banana consumption is approximately 250 kg per person. This fact, in addition to the agronomic properties of staple banana cultivars such as vegetative reproduction and continuous cropping, make bananas an ideal target for pVA enhancement through genetic engineering. Interestingly, there are banana varieties known with high fruit pVA content (up to 27.8 ìg/g dry weight), although they are not widely consumed due to factors such as cultural preference and availability. The genes involved in carotenoid accumulation during banana fruit ripening have not been well studied and an understanding of the molecular basis for the differential capacity of bananas to accumulate carotenoids may impact on the effective production of genetically engineered high pVA bananas. The production of phytoene by the enzyme phytoene synthase (PSY) has been shown to be an important rate limiting determinant of pVA accumulation in crop systems such as maize and rice. Manipulation of this gene in rice has been used successfully to produce Golden Rice, which exhibits higher seed endosperm pVA levels than wild type plants. Therefore, it was hypothesised that differences between high and low pVA accumulating bananas could be due either to differences in PSY enzyme activity or factors regulating the expression of the psy gene. Therefore, the aim of this thesis was to investigate the role of PSY in accumulation of pVA in banana fruit of representative high (Asupina) and low (Cavendish) pVA banana cultivars by comparing the nucleic acid and encoded amino acid sequences of the banana psy genes, in vivo enzyme activity of PSY in rice callus and expression of PSY through analysis of promoter activity and mRNA levels. Initially, partial sequences of the psy coding region from five banana cultivars were obtained using reverse transcriptase (RT)-PCR with degenerate primers designed to conserved amino acids in the coding region of available psy sequences from other plants. Based on phylogenetic analysis and comparison to maize psy sequences, it was found that in banana, psy occurs as a gene family of at least three members (psy1, psy2a and psy2b). Subsequent analysis of the complete coding regions of these genes from Asupina and Cavendish suggested that they were all capable of producing functional proteins due to high conservation in the catalytic domain. However, inability to obtain the complete mRNA sequences of Cavendish psy2a, and isolation of two non-functional Cavendish psy2a coding region variants, suggested that psy2a expression may be impaired in Cavendish. Sequence analysis indicated that these Cavendish psy2a coding region variants may have resulted from alternate splicing. Evidence of alternate splicing was also observed in one Asupina psy1 coding region variant, which was predicted to produce a functional PSY1 isoform. The complete mRNA sequence of the psy2b coding regions could not be isolated from either cultivar. Interestingly, psy1 was cloned predominantly from leaf while psy2 was obtained preferentially from fruit, suggesting some level of tissue-specific expression. The Asupina and Cavendish psy1 and psy2a coding regions were subsequently expressed in rice callus and the activity of the enzymes compared in vivo through visual observation and quantitative measurement of carotenoid accumulation. The maize B73 psy1 coding region was included as a positive control. After several weeks on selection, regenerating calli showed a range of colours from white to dark orange representing various levels of carotenoid accumulation. These results confirmed that the banana psy coding regions were all capable of producing functional enzymes. No statistically significant differences in levels of activity were observed between banana PSYs, suggesting that differences in PSY activity were not responsible for differences in the fruit pVA content of Asupina and Cavendish. The psy1 and psy2a promoter sequences were isolated from Asupina and Cavendish gDNA using a PCR-based genome walking strategy. Interestingly, three Cavendish psy2a promoter clones of different sizes, representing possible allelic variants, were identified while only single promoter sequences were obtained for the other Asupina and Cavendish psy genes. Bioinformatic analysis of these sequences identified motifs that were previously characterised in the Arabidopsis psy promoter. Notably, an ATCTA motif associated with basal expression in Arabidopsis was identified in all promoters with the exception of two of the Cavendish psy2a promoter clones (Cpsy2apr2 and Cpsy2apr3). G1 and G2 motifs, linked to light-regulated responses in Arabidopsis, appeared to be differentially distributed between psy1 and psy2a promoters. In the untranscribed regulatory regions, the G1 motifs were found only in psy1 promoters, while the G2 motifs were found only in psy2a. Interestingly, both ATCTA and G2 motifs were identified in the 5’ UTRs of Asupina and Cavendish psy1. Consistent with other monocot promoters, introns were present in the Asupina and Cavendish psy1 5’ UTRs, while none were observed in the psy2a 5’ UTRs. Promoters were cloned into expression constructs, driving the â-glucuronidase (GUS) reporter gene. Transient expression of the Asupina and Cavendish psy1 and psy2a promoters in both Cavendish embryogenic cells and Cavendish fruit demonstrated that all promoters were active, except Cpsy2apr2 and Cpsy2apr3. The functional Cavendish psy2a promoter (Cpsy2apr1) appeared to have activity similar to the Asupina psy2a promoter. The activities of the Asupina and Cavendish psy1 promoters were similar to each other, and comparable to those of the functional psy2a promoters. Semi-quantitative PCR analysis of Asupina and Cavendish psy1 and psy2a transcripts showed that psy2a levels were high in green fruit and decreased during ripening, reinforcing the hypothesis that fruit pVA levels were largely dependent on levels of psy2a expression. Additionally, semi-quantitative PCR using intron-spanning primers indicated that high levels of unprocessed psy2a and psy2b mRNA were present in the ripe fruit of Cavendish but not in Asupina. This raised the possibility that differences in intron processing may influence pVA accumulation in Asupina and Cavendish. In this study the role of PSY in banana pVA accumulation was analysed at a number of different levels. Both mRNA accumulation and promoter activity of psy genes studied were very similar between Asupina and Cavendish. However, in several experiments there was evidence of cryptic or alternate splicing that differed in Cavendish compared to Asupina, although these differences were not conclusively linked to the differences in fruit pVA accumulation between Asupina and Cavendish. Therefore, other carotenoid biosynthetic genes or regulatory mechanisms may be involved in determining pVA levels in these cultivars. This study has contributed to an increased understanding of the role of PSY in the production of pVA carotenoids in banana fruit, corroborating the importance of this enzyme in regulating carotenoid production. Ultimately, this work may serve to inform future research into pVA accumulation in important crop varieties such as the EAHB and the discovery of avenues to improve such crops through genetic modification.

Antioxidant properties of carotenoids in vitro and in vivo

Carotenoids are a class of natural pigments familiar to all through the orange-red to yellow colors of many fruits, vegetables, and flowers, as well as for the provitamin A activity that some of them possess. A body of scientific evidence suggests that carotenoids may scavenge and deactivate free radicals, acting thereby as antioxidants both in food systems (in vitro) and in the human organism (in vivo). Overall, epidemiological evidence links higher carotenoid intakes and tissue concentrations with reduced cancer and cardiovascular disease risk. However, research has also shown that the antioxidant activity of carotenoids may shift to a prooxidant character depending mainly on the biological environment in which they act. A summary of the antioxidant potential of natural carotenoids both in oil model systems and in vivo is presented in this article.