Heritability of polyphenols, anthocyanins and antioxidant capacity of Cameroonian cocoa (Theobroma cacao L.) beans

This study investigates the heritability of polyphenolic, anthocyanin and antioxidant capacity of beans derived from four cocoa clones and their offsprings. These compounds were analyzed at 280 nm (polyphenols) and 520 nm (anthocyanins) by reversed-phase high-performance liquid chromatography (RP-HPLC) method using a photodiode array detector (PDA). The antioxidant capacity of methanolic extracts prepared from cocoa beans was measured by the DPPH and ABTS assays. Samples displayed catechin and epicatechin as the two main polyphenols. Epicatechin, which represents 1 to 5% of defatted cocoa seed powder, was hundred-fold higher than catechin while cyanidin-3-arabinoside was three-fold higher than cyanidin-3-galactoside. The two main anthocyanins found in our samples represent about 0.05% of defatted cocoa seed powder. All these compounds were genotype-dependent. Unidentified substances called A, B and C were also found in cocoa seeds. Substance A is discussed as a derivative of caffeic acid and an ester-bound compound. Substances B and C are oligomers of proanthocyanidins. Antioxidant capacity of cocoa beans obtained by 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay was higher than those obtained by DPPH assay. According to correlation tests, flavanols contributed better in the antioxidant capacity than anthocyanin. No maternal effect was detected in the transmission of polyphenol compounds suggesting a nuclear heritability.Key words: Theobroma cacao, cocoa beans, polyphenolic compounds, anthocyanins, heritability

HETEROSIS AND HERITABILITY ESTIMATES OF PURINE ALKALOIDS AND POLYPHENOLS IN COCOA

Cocoa ( Theobrama cacao L. ) is an important allogamous tropical tree crop, whose centre of diversity is considered to be in Central America. Dry cocoa beans from five cocoa clones, and their intercrossed hybrids were analysed based on the variation of alkaloids and polyphenolic compounds contents, in order to gain insights on the heterosis and broad-sense heritability. Polyphenols and alkaloids were analysed at 280 nm by HPLC, using a Photodiode Array Detector (PDA); while anthocyanins were separated with the SEP-PAK Vac 6cc 1000 mg (waters) column and measured at 520 nm with a PDA. Dry cocoa beans displayed high content of purine alkaloids (2.1 and 8.8 mg g-1 for caffein and theobromine, respectively), and polyphenols (25 and 2978 \ub5g g-1 for catechin and epicatechin, respectively). Among the five cocoa clones, SNK16 was the highest in purine alkaloid (caffein and theobromin) and flavanol (catechin and epicatechin); while T79/467 possessed the greatest quantity of cyanidin-3-galactoside and cyanidin-3-arabinoside. From all the parameters studied, anthocyanins (Cyanidin-3-galactoside and cyanidin-3-arabinoside) exhibited the highest level of heterosis. Parental genotypes SNK16 and T79/467 showed good aptitudes for the combination of characters because their reciprocal hybrids F5 and F9, distinguished themselves by better levels of mid-parent heterosis values. Besides, the heritability value in strict sense of this Cyanidin-3-galactoside was very high. Absence of significant difference between genotypes, coming from reciprocal crossbreeding for Cyanidin-3-galactoside, suggests that this character in cocoa would be nuclear contrary to purine alkaloids and flavan-3-ols, where their transmission to offsprings can be stated as cytoplasmic.Le cacaoyer ( Theobrama cacao L. ) est une importante plante tropicale allogame originaire d\u2019Am\ue9rique Centrale. Les teneurs en alcalo\uefdes et en polyph\ue9nols ont \ue9t\ue9 analys\ue9es sur des f\ue8ves de cinq clones de cacao et de leurs descendants issus des croisements r\ue9ciproques afin de d\ue9terminer l\u2019h\ue9t\ue9rosis et l\u2019h\ue9ritabilit\ue9 de ces m\ue9tabolites. Les alcalo\uefdes et les polyph\ue9nols ont \ue9t\ue9 analys\ue9s par HPLC \ue0 280nm utilisant un d\ue9tecteur \ue0 barrettes de photodiode (PDA) alors que les anthocyanines l\u2019ont \ue9t\ue9 sur une colonne SEP-PAK Vac 6cc 1000 mg \ue0 520nm utilisant le PDA. Ces f\ue8ves ont des teneurs \ue9lev\ue9es en alcalo\uefdes puriques (2,1 et 8,8 mg.g-1 de caf\ue9ine et de th\ue9obromine respectivement) et en polyph\ue9nols (25 \ub5g.g-1 de cat\ue9chine et 2978 \ub5g.g-1 d\u2019epicat\ue9chine). Des cinq clones utilis\ue9s, SNK16 s\u2019est distingu\ue9 par des teneurs les plus \ue9lev\ue9es en caf\ue9ine, th\ue9obromine, cat\ue9chine et \ue9picat\ue9chine. De tous les param\ue8tres analys\ue9s, les anthocyanines ont montr\ue9 un niveau d\u2019h\ue9t\ue9rosis \ue9lev\ue9. Les g\ue9notypes SNK16 et T79/467 ont pr\ue9sent\ue9 une meilleure aptitude \ue0 la combinaison et les hybrides issus de leur croisement r\ue9ciproque (F5 et F9) ont pr\ue9sent\ue9 une meilleure h\ue9t\ue9rosis par rapport au meilleur parent. L\u2019utilisation de ces deux clones dans un champ semencier serait tr\ue8s importante pour des industries pharmaceutiques car leur croisement g\ue9n\ue8re des hybrides \ue0 haut potentiel en alcalo\uefdes et en polyph\ue9nols. De plus, l\u2019absence d\u2019une diff\ue9rence significative de cyanidine-3-galactoside entre hybrides r\ue9ciproques sugg\ue8re que l\u2019h\ue9ritabilit\ue9 de ce caract\ue8re serait nucl\ue9aire contrairement aux alcalo\uefdes puriques et aux flavan-3-ols dont l\u2019h\ue9ritabilit\ue9 serait de nature cytoplasmique

Biochemical profile of cuttings used for in vitro organogenesis of Prunus africana: An endangered species in Cameroon

Prunus africana (Kanda stick) is a valuable medicinal tree classified as priority species for domestication in Cameroon. To measure the ability for developing axillary buds and multiple shoots in relation with the origin and state of explants, some biochemical parameters were assessed in eight types of single-node cuttings. These cuttings were treated with different concentrations of kinetin (kin) indole butyric acid (IBA) and thidiazuron (TDZ) and cultured in Murashige and Skoog (MS) medium. The glutelin content (1.13 ± 0.201 µg/mg FW) was higher compared to those of total albumin, globulin and prolamin and most representative at mature vegetative apical stage (MVA). The highest (15.60 ± 1.966 µg/mg FW) and lower (2.82 ± 0.072 µg/mg FW) amount of phenol compound was observed in the mature dormant stages and immature vegetative distal stage (IVD), respectively. Regarding the peroxidases, highest activity (0.453 ± 0.055 OD/mg/ FW.5 min-1) was obtained in mature dormant apical stage. Apart from IVA state, there was no reactive explant cultured in vitro. The high percentage of budding and proliferation of budding (100%) and rooting (100%) were achieved with 12 μM Kin and 24 μM IBA, respectively. In the presence of 24 μM TDZ, multiple shoot was induced with a maximum of 5 shoots/explants. Micropropagation success of P. africana is influenced by cytokinin, physiological and biochemical status of single node cutting.Key words: Biochemical profile, Prunus africana, budding, multiple shoots, rooting

VARIATION OF b-1,3-GLUCANASE, CHITINASE AND POLYPHENOLOXIDASE ACTIVITIES IN CACAO PODS UPON Phytophthora megakarya INOCULATION

Cacao (Theobroma cacao   L.) clones that differ in susceptibility to black pod disease were analysed for response to stress induced by pod inoculation with the fungus Phytophthora megakarya   Braz. Et Griff. Fungal inoculation significantly stimulated β-1,3-glucanase activity in both soluble and ionically-bound fractions of the less susceptible clones. No significant correlation was found in the other clones. Chitinase activity in both soluble and ionically-bound fractions was generally reduced upon pod inoculation with the fungus, but this pattern did not correlate with disease severity. Polyphenoloxidase activity, following pod inoculation, was genotype dependent in the soluble fractions, whereas in the ionically-bound fractions, stimulation of this activity was recorded in the less susceptible clones. Moreover, pod inoculation was characterised by the appearance of a new polyphenoloxidase isoform A'2 in the less susceptible clones

Variation of β-1,3-Glucanase, Chitinase and Polyphenoloxidase Activities in Cacao Pods upon Phytophthora megakarya Inoculation

Cacao (Theobroma cacao L.) clones that differ in susceptibility to black pod disease were analysed for response to stress induced by pod inoculation with the fungus Phytophthora megakarya Braz. Et Griff. Fungal inoculation significantly stimulated β-1,3-glucanase activity in both soluble and ionically-bound fractions of the less susceptible clones. No significant correlation was found in the other clones. Chitinase activity in both soluble and ionically-bound fractions was generally reduced upon pod inoculation with the fungus, but this pattern did not correlate with disease severity. Polyphenoloxidase activity, following pod inoculation, was genotype dependent in the soluble fractions, whereas in the ionically-bound fractions, stimulation of this activity was recorded in the less susceptible clones. Moreover, pod inoculation was characterised by the appearance of a new polyphenoloxidase isoform A\'2 in the less susceptible clones. Key Words: Absorbance, cortex, ionically-bound, Theobroma cacao, wonding Résumé Les réponses aux stress induits par innoculation de gousses de cacao (Theobroma cacao L.), aux susceptibilités differentes à la maladie de Blackpod, par le Phytophthora megakarya Braz étaient analysées. L\'inoculation de fungi a significativement stimulé les activités de « glucanase » β-1,3 dans les deux fractions solubles et à liaison ionique des clones moins susceptibles. Pas des corrélations significatives étaient observées dans d\'autres clones. L\'activité de la chitanase dans les deux milieux était generalement reduite juste après l\'inoculation par le fongi, mais cette tendance n\'a pas corrélée avec la sévérité de la maladie. L\'activité du polyphenoloxidase, après inoculation de gousses, était généralement dependante du génotype dans la fraction soluble, alors que la stimulation de cette activité était observée dans les clones moins susceptibles. En plus, l\'inoculation des gousses était caracterisée par l\'apparition de nouveau polyphenolosidase isoformes A\'2 dans les clones les moins susceptibles. Mots Clés: Absorbance, cortex, ionically-bound, Theobroma cacao, wonding (Af Crop Sci J 2003 Vol 11 No 2 pp.97-106

Micropropagation and effect of phloroglucinol on rooting of Diospyros crassiflora Hiern

Open Access Journal; Published online: 05 Mar 2020The jet-black to streaked ebony wood produced by the African ebony (Diospyros crassiflora Hiern, Ebenaceae) is exploited in Central and West Africa. A conservation effort is currently underway in Cameroon to propagate the tree through seedlings and cuttings. However, the intermittent availability of its seeds and the long time required for rooting formation of cuttings are limiting its propagation. This study aims to develop a successful protocol for ebony micropropagation. In vitro culture of nodal segments from seedlings was performed in half-strength Murashige and Skoog (MS) medium supplemented with either zeatin (0.0, 2.3, 4.6, 9.1, 13.7, 18.2, 22.8, and 27.4 µm) or 6-benzylaminopurine (BAP) (0.0, 2.2, 4.4, 8.8, 13.3, 17.8, 22.2, and 26.6 µm). After 12 weeks, all media allowed shoot budbreak. Shoots displaying the greatest budbreak were observed with 22.8 µm zeatin and 22.2 µm BAP. The shoots were then transferred to a medium supplemented with indole-3-butyric acid (IBA) and phloroglucinol (PG) at different concentrations for root induction. Root induction was observed on the shoots initially induced in the medium with BAP, but not in those grown in the medium with zeatin. In half-strength MS supplemented with 396.5 µm PG plus 14.2 µm IBA, the formation of a single tap root was observed on 79% of shoots, with an average root length of 2.8 ± 0.18 cm. Rooted plants were successfully acclimatized to the greenhouse, with a 50% survival rate. This is the first report on Diospyros crassiflora micropropagation, which paves the way for rapid ebony multiplication to respond to needed conservation efforts

Cassava postharvest physiological deterioration: a complex phenomenon involving calcium signaling, reactive oxygen species and programmed cell death.

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