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The banana lectin from Musa paradisiaca, MW 29.4 kDa, has been isolated, purified and crystallized. The trigonal crystals contain one dimeric molecule in the asymmetric unit. The structure has been solved using molecular replacement to a resolution of 3 A. The structure of the subunit is similar to that of jacalin-like lectins.
Two antifungal phenyl-phenalenone phytoalexins isolated from the banana plant (Musa acuminata) elicited with the fungus Fusarium oxysporum, together with a methoxy derivative of one of them and two epoxide precursors of their chemical synthesis, were tested for leishmanicidal activity on Leishmania donovani promastigotes and L. infantum amastigotes. Drugs inhibited proliferation of both forms of the parasite with a 50% lethal concentration range between 10.3 and 68.7 micro g/ml. Their lethal mechanism was found linked to the respiratory chain by a systematic approach, including electron microscopy, measurement of the oxygen consumption rate on digitonin-permeabilized promastigotes, and enzymatic assays on a mitochondrial enriched fraction. Whereas the whole set of compounds inhibited the activity of fumarate reductase in the mitochondrial fraction (50% effective concentration [EC(50)] between 33.3 and 78.8 micro g/ml) and on purified enzyme (EC(50) = 53.3 to 115 micro g/ml), inhibition for succinate dehydrogenase was only observed for the two phytoalexins with the highest leishmanicidal activity: anigorufone and its natural analogue 2-methoxy-9-phenyl-phenalen-1-one (EC(50) = 33.5 and 59.6 micro g/ml, respectively). These results provided a new structural motif, phenyl-phenalenone, as a new lead for leishmanicidal activity, and support the use of plant extracts enriched in antifungal phytoalexins, synthesized under fungal challenge, as a more rational and effective strategy to screen for new plant leishmanicidal drugs.
Diabetes mellitus is a debilitating hormonal disorder in which strict glycemic control and prevention of associated complications are of crucial importance. This study was designed to evaluate the hypoglycemic effect of methanolic extract of mature, green fruits of Musa paradisiaca (MEMP) in normal (normoglycemic) and streptozotocin (STZ)-treated, diabetic (hyperglycemic) mice, using chlorpropamide as the reference antidiabetic agent. MEMP (100-800 mg/kg p.o.) induced significant, dose-related (p < 0.05-0.001) reductions in the blood glucose concentrations of both normal and diabetic mice. Chlorpropamide (250 mg/kg p.o.) also produced significant (p < 0.01-0.001) reductions in the blood glucose concentrations of normal and diabetic mice. The results of this experimental study indicate that, in the mammalian model used, MEMP possesses hypoglycemic activity. Although the precise mechanism of the hypoglycemic action of MEMP is still unclear and will have to await further studies, it could be due, at least in part, to stimulation of insulin production and subsequent glucose utilization. Nevertheless, the findings of this experimental animal study indicate that MEMP possesses hypoglycemic activity, and thus lends credence to the suggested folkloric use of the plant in the management and/or control of adult-onset, type-2 diabetic mellitus among the Yoruba-speaking people of South-Western Nigeria.
The photosynthetic rate (Pn) in leaves of Musa paradisiaca grown under elevated CO2 concentration (700 +/- 56 microliters.L-1) for one week was 5.14 +/- 0.32 mumol.m-2.s-1, 22.1% higher than that under ambient CO2 concentration, while under elevated CO2 concentration for 8 week, the Pn decreased by 18.1%. It can be inferred that the photosynthetic acclimation to elevated CO2 concentration and the Pn inhibition occurred in leaves of M. paradisiaca. The respiration rate in light (Rd) was lower in leaves under higher CO2 concentration, compared with that under ambient CO2 concentration. If the respiration in light was not included, the difference in CO2 compensation point for the leaves of both plants was not significant. Under higher CO2 concentration for 8 weeks, the maximum carboxylation rate(Vcmax) and electron transportation rate (J) in leaves decreased respectively by 30.5% and 14.8%, compared with that under ambient CO2 concentration. The calculated apparent quantum yield (alpha) in leaves under elevated CO2 concentration according to the initial slope of Pn/PAR was reduced to 0.014 +/- 0.010 molCO2.mol-1 quanta, compared with the value of 0.025 +/- 0.005 molCO2.mol-1 quanta in the control. The efficiency of light energy conversion also decreased from 0.203 to 0.136 electrons.quanta-1 in plants under elevated CO2 concentration. A lower partitioning coefficient for leaf nitrogen in Rubisco, bioenergetics and thylakoid light-harvesting components was observed in plants under higher CO2 concentration. The results indicated that the multi-process of photosynthesis was suppressed significantly by a long-term (8 weeks) higher CO2 concentration incubation.
Studies with plantain banana (Musa sapientum var. paradisiaca) have indicated its ulcer protective and healing activities through its predominant effect on various mucosal defensive factors [Sanyal et.al, Arch Int Pharmacodyn, 149 (1964) 393; 155 (1965) 244]. Oxidative stress and Helicobactorpylori colonization are considered to be important factors in the pathogenesis of gastric ulcers. In the present study methanolic extract of plantain banana pulp (BE) was evaluated for its (i) antiulcer and antioxidant activities in 2 hr cold restraint stress and (ii) anti-H.pylori activity in vitro. The extract (BE, 50 mg/kg, twice daily for 5 days) showed significant antiulcer effect and antioxidant activity in gastric mucosal homogenates, where it reversed the increase in ulcer index, lipid peroxidation and super oxide dismutase values induced by stress. However it did not produce any change in catalase values, which was significantly decreased by stress. Further, in the in vitro study. BE (0.32-1,000 microg/ml) did not show any anti-H.pylori activity. The results suggest absence of anti-H. pyloric activity of methanolic extract of banana in vitro and its antioxidant activity may be involved in its ulcerprotective activity.
To establish an improved protocol for the cryopreservation of banana (Musa spp.), a fast-freeze/fast-thaw method was applied and compared to three existing cryogenic procedures, namely, simple freezing, vitrification of proliferating meristems and vitrification of individual meristems. The average post-thaw shoot regeneration of the fast freeze/fast thaw protocol was 51.8 percent and was superior to the existing protocols which were 12.5 percent, 39.2 percent and 42.8 percent, respectively. Other factors such as time and ease of operation were considered for each method. It was found that the fast freeze and fast thaw technique was the best amongst all the four methods tested for the cryopreservation of in vitro banana meristems in the genotype Robusta (AAA).
Two primitive diploid Musa cultivars, Matti and Chemmatti from the extreme southern part of the Western Ghats were multiplied by in vitro culture of sucker-derived shoot apices. Decontaminated corm explants (1 cm x 1 cm) having shoot apex (approximately 0.3 cm) cultured for 1 month in Murashige and Skoog basal agar medium was cut vertically into eight segments and each segment having a part of shoot meristem was cultured in presence of 6-benzylaminopurine (BAP) and combinations of BAP and indole-3-acetic acid (IAA) or indole-3-butyricacid (IBA) to produce multiple shoots. After 12 weeks of culture, maximum number of shoots (32) in both the cultivars were produced in approximate 60% of the explants in presence of BAP and IAA each at 1.5 mg/l(-1) (Matti) and 40% of the explants in 2.5 mg/l(-1) of BAP and 1.5 mg/l(-1) of IAA (Chemmatti). Buds were formed from the base of the subcultured shoots and somewhat more number (34) of shoots were obtained in Matti than in Chemmatti (31) after 8 weeks. Difference in the concentration of cytokinin required for shoot initiation and multiplication, persistence of exudation through the subculture and red colouration of the early formed sheathing leaf bases in the shoots in Chemmatti indicated possible genotypic differences between the two cultivars. Multiple shoot proliferation achieved through five subcultures of the isolated shoots without any decline. Transfer of shoots (4-5 cm) into MS basal medium favoured rooting in 4 weeks and rooted plants (9 cm) were hardened and established (80-95%). Mericlones of Matti cultivated in homesteads produced bunches of uniform characters in 13 months.
In México, the banana (Musa paradisiaca) is cooked (boiling or deep frying) before being eaten, but the consumption is not very popular and a big quantity of the product is lost after harvesting. The unripe plantain has a high level of starch and due to this the use of banana can be diversified as raw material for starch isolation. The objective of this work was to study the starch yield at pilot plant scale. Experiments at laboratory scale were carried out using the pulp with citric acid to 0,3 % (antioxidant), in order to evaluate the different unitary operations of the process. The starch yield, based on starch presence in the pulp that can be isolated, were between 76 and 86 %, and the values at pilot plant scale were between 63 and 71 %, in different lots of banana fruit. Starch yield values were similar among the diverse lots, showing that the process is reproducible. The lower values of starch recovery at pilot plant scale are due to the loss during sieving operations; however, the amount of starch recovery is good.
BACKGROUND & OBJECTIVE: A group of villages in Kollam district of Kerala, southern part of India are exposed to a higher dose of natural radiation than global average. Yet no adverse health effects have been found in humans, animals and plants in these areas. The present study was carried out to understand whether radiation affects the quantity and quality of flavonoids in plants grown in this area of high radiation, and to assess the effect of feeding flavonoid rich fraction (FRF) of the two varieties of banana to rats on their biochemical parameters like lipids, lipid peroxides and antioxidant enzyme levels. METHODS: A total of 42 albino rats were equally divided into 7 groups. Rats fed laboratory diet alone were grouped under group I (normal control). Groups II and V received flavonoid rich fraction (FRF) from the fruits of two varieties of Musa paradisiaca, Palayamkodan and Rasakadali respectively from normal background radiation area (Veli) and treated as controls. Rats of groups III and IV received FRF of Palayamkodan from high background radiation areas (HBRAs) - Neendakara and Karunagappally respectively while groups VI and VII received FRF of Rasakadali from HBRAs. At the end of the experimental period of 45 days, lipids, lipid peroxides and antioxidant enzymes from liver, heart and kidney were analyzed. RESULTS: FRF of Palayamkodan and Rasakadali varieties showed significant hypolipidaemic and antioxidant activities. But these activities were found to be lowered in plants grown in HBRAs, particularly in Karunagappally area. Of the two, Palayamkodan variety was more effective in reducing lipids and lipid peroxides. MDA and hydroperoxides were significantly diminished in rats given FRF of banana from Veli (control area) only. FRF from plants grown in HBRAs exerted inhibition in the activities of antioxidant enzymes in the liver of rats and this inhibitory effect was maximum in rats fed FRF from Karunagappally. INTERPRETATION & CONCLUSION: Banana grown in HBRAs is of lower quality with less efficient antioxidant system. Palayamkodan was superior with its effect on hypolipidaemic and antioxidant activities. High background radiation seems to have no enhancing effect on the radioprotective action of flavonoids of banana and thereby to those consuming these fruits.
Beta-galactosidase is thought to be involved in fruit softening through cleaving beta(1-->4) galactan bonds in cell wall hemicellulose. To study the relationship between fruit softening and beta-Gal during banana (Musa sp.) fruit ripening, a beta-Gal cDNA fragment, named MA-Gal, has been cloned from banana fruit pulp using RT-PCR in this study. The results of sequence analysis showed that MA-Gal contained 927 bp, encoding a polypeptide of 309 amino acids, the deduced protein was highly homologous to plant beta-galactosidase expressed in fruit ripening. The MA-Gal putative amino acids have five homologous domains (typical eukaryotic beta-Gals have seven domains), contain the GGPIILSQIENEY(F) motif, which is a presumptive catalytic active site conserved in all beta-Gals. Phylogenetic analysis showed that MA-Gal was in plant beta-Gal group I, which was expressed in fruit tissue. The changes in beta-Gal activity and firmness in pulp during three different stages were also assayed. The Northern analysis showed that the MA-Gal transcripts in pulp were detected at low level at preclimacteric stage, while an increasing progression was observed during fruit ripening, and the highest transcript amount was found at the postclimacteric stage. These results suggest that MA-Gal may play a role during banana fruit ripening and softening.
Musa sapientum commonly known as 'banana' is widely used in Indian folk medicine for the treatment of diabetes mellitus. Oral administration of 0.15, 0.20 and 0.25 g/kg body weight of the chloroform extract of the flowers for 30 days resulted in a significant reduction in blood glucose and glycosylated haemoglobin and an increase in total haemoglobin. The extract prevented a decrease in body weight, and also resulted in a decrease in free radical formation in the tissues. Thus the study shows that banana flower extract (BFEt) has an antihyperglycaemic action. The decrease in thiobarbituric acid reactive substances (TBARS) and the increase in reduced glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) clearly shows the antioxidant property of BFEt. The effect of BFEt was more prominently seen in the case of animals given 0.25 g/kg body weight. BFEt was more effective than glibenclamide.
The sequence-tagged microsatellite site (STMS) discrimination potential was explored using nine microsatellite primer pairs. STMS polymorphism was assayed by nonradioactive urea-polyacrylamide gel electrophoresis. Genetic relationships were examined among 59 genotypes of wild or cultivated accessions of diploid Musa acuminata. The organization of the subspecies was confirmed and some clone relationships were clarified.
Banana is one of the most important subtropical crops. The genetic system, however, is relatively unknown and is complicated by specific interhybridization, heterozygosity, and polyploidy, which are common in most clones. These factors make identification of closely related banana cultivars difficult, particularly when sterile. Amplified fragment length polymorphism (AFLP) analysis using eight primer combinations was carried out on 16 banana cultivars. Results showed that AFLP could be used to distinguish the different cultivars by their unique banding patterns. Unique AFLP molecular markers were detected for 12 banana cultivars, which can be used to develop specific probes for identification purposes. The cluster analysis also revealed the need for a link between genotype studies using molecular techniques and the current system of classification of Musa cultivars based purely on morphological traits.
Restriction fragment length polymorphisms (RFLPs) were used as markers to determine the transmission of cytoplasmic DNA in diploid banana crosses. Progenies from two controlled crosses were studied with heterologous cytoplasmic probes. This analysis provided evidence for a strong bias towards maternal transmission of chloroplast DNA and paternal transmission of mitochondrial DNA in Musa acuminata. These results suggest the existence of two separate mechanisms of organelle transmission and selection, but no model to explain this can be proposed at the present time. Knowledge of the organelle mode of inheritance constitutes an important point for phylogeny analyses in bananas and may offer a powerful tool to confirm hybrid origins.
Banana mild mosaic virus (BanMMV) is a previously undescribed filamentous virus infecting Musa spp. The complete genome has been sequenced from PCR clones and consists of 7352 nucleotides, encoding five open reading frames (ORFs) of 205, 25.5, 12.4, 8.0 and 26.8 kDa, respectively. BanMMV was most closely related to fovea- and carlaviruses, based on phylogenetic analysis using a portion of the viral replicase. Analysis of other parts of the genome revealed similarities with fovea-, carla- and potexviruses, but the virus was not clearly aligned to any previously recognised genus.
Chemical analyses for the elementary compositions of the ashes of the fruit peels and trunks of the tropical plantain Musa paradisiaca have been undertaken. The elements, categorized as trace elements, generally are found to have higher mean concentrations in the fruit peels than in the trunks (except in the case of Zn). Their peel-trunk uptake ratios have been calculated and range between 1 and 4, showing normal levels of accumulations in the fruit peels over the trunks.
Orally administered banana pulp powder (Musa sapientum var. paradisiaca) was shown to have significant anti-ulcerogenic activity in rats subjected to aspirin, indomethacin, phenylbutazone, prednisolone and cysteamine and in guinea-pigs subjected to histamine. Banana powder not only increased mucosal thickness but also significantly increased [3H]thymidine incorporation into mucosal DNA. Relative to untreated control sections, histological studies showed that banana treatment increased staining by alcian blue in the apical cells with staining noted in the deeper layers of the mucosal glands. Banana-treated and control sections were also stained for DNA by the Feulgen reaction. The banana-treated sections showed a greater aggregation and intensity of pink spots when compared to controls. The present study suggests that banana powder treatment not only strengthens mucosal resistance against ulcerogens but also promotes healing by inducing cellular proliferation.
Banana pulp powder (Musa sapientum Linn. var. paradisiaca) was studied for its effects on gastric mucosal resistance. Banana-treated (0.5 g/kg orally, twice daily for 3 days) rats of either sex showed: (i) a significant increase in the [3H]thymidine incorporation into mucosal cell DNA; (ii) a significant increase in the total carbohydrate (sum of total hexoses, hexosamine, fucose and sialic acid) content of gastric mucosa; (iii) a significant decrease in gastric juice DNA and protein; (iv) a significant increase in the total carbohydrates and carbohydrate/protein ratio of gastric juice. Aspirin treatment to rats caused similar effects as banana on the [3H]thymidine incorporation into mucosal cell DNA but showed opposite effects on the other parameters. These results suggest that banana treatment increased and aspirin decreased the gastric mucosal resistance as evidenced by a respective decrease and increase in gastric juice DNA, the latter serving as an index of the rate of mucosal shedding. Increased cellular mucus may be the factor for increased mucosal resistance. The results of the present study tend to confirm that plantain banana powder strengthens mucosal resistance and promotes the healing of ulcers.