Effects of Carica papaya peel meal-based diets on rabbit bucks' spermiogram and reaction time.

The study aimed to evaluate the effects of Carica papaya peel meal-based diet on spermiogram and reaction time in rabbit bucks. Ripe pawpaw fruits were harvested during the dry season. The peels were carefully removed from the pulp and sun-dried for a week. Afterward, they were ground and included in the test diets as pawpaw peel meal (PPM) at inclusion rates of 0%, 15%, and 30%. Rabbit bucks (n = 15) were randomly separated into three groups of five bucks and labeled as groups A, B, and C. Group A, the control group (0%), was fed the basal protein diet (BD), group B (PPM 15) was given a PPM-based diet (15%), while C (PPM 30) was given diet composed of PPM (30%). Semen samples were collected and evaluated fortnightly for 14 weeks. The reaction time and mean ejaculate volume were lower (P < 0.05) in the treatment groups than in the control. Sperm motility and concentration decreased significantly (P < 0.05) across the groups from week 4 to the end of the experiment. Bucks fed PPM 15%, and PPM 30% had significantly (P < 0.05) higher percentages of dead sperm cells and total spermatozoa abnormalities. The control had (86%) normal spermatozoa morphology while those of PPM 15% and PPM 30% were (61%) and (52%), respectively. PPM 30% had the highest abnormal spermatozoa (47%) compared to PPM 15% (38%) and control (13%). The findings indicate that pawpaw peels up to 15% and 30% in the diet have a negative effect on spermiogram.

Growth performance and nutrient digestibility of growing rabbits fed diets containing pawpaw (Carica papaya L.) leaf protein concentrate.

This experiment was carried out to evaluate the growth performance and nutrient digestibility of growing rabbits fed diets containing pawpaw (Carica papaya L.) leaf protein concentrate as partial replacement for soybean meal (SBM). Five dietary treatments were formulated such that SBM was replaced with pawpaw leaf protein concentrate (PLPC) at 0, 15, 30, 45, and 60% weight-for-weight. Twenty-five composite growing rabbits of mixed sex and approximately seven weeks of age (736±90 g) were randomly allocated to five dietary treatments of five replicates in a completely randomized design. The rabbits had access to water and the experimental feed ad libitum for 12 weeks of feeding trial after one week of adaptation. Results showed that the growth performance and nutrient digestibility of rabbits recorded in this experiment were not significantly affected (p>0.05) by the replacement of SBM with PLPC, indicating that PLPC can be used to replace soybean meal up to 60% weight-for-weight without causing any adverse effect on the growth performance and nutrient digestibility of rabbits. The average water-to-feed ratio was 2.54, indicating that rabbit under this condition of experiment requires an average of 2.54 mL of water for every 1 g of feed consumed. The flesh-to-bone ratio of rabbits recorded in this study was between 3.06±0.36 and 3.22±0.22. Rabbits on diets in which 60% SBM was replaced with PLPC resulted in the highest savings in terms of cost differential (₦90.94/kg); therefore, it is cheaper for farmers to replace SBM with PLPC at 60% weight-for-weight in rabbit feeding in Nigeria.

Effects of Pawpaw (Asimina triloba) Seed Extract on the Differentiation and Fat Accumulation of 3T3-L1 Cells under Different Glucose Conditions.

Asimina triloba (pawpaw) contains various bioactive alkaloids and acetogenins. In the present study, the effects of pawpaw seed extract (PSE) on adipocyte differentiation and fat accumulation were investigated in 3T3-L1 cells under different glucose conditions. Treatment of undifferentiated cells with 10 ng/mL PSE increased lactic acid production, suggesting enhanced anaerobic glycolysis. PSE treatment also suppressed cell proliferation and decreased the nicotinamide adenine dinucleotide (NAD)+/NADH ratio in low-glucose medium; however, this effect was not observed in high-glucose medium. Additionally, PSE treatment under low-glucose conditions resulted in reduced accumulation of triglycerides and decreased expression of peroxisome proliferator-activated receptor (PPAR)-γ, CAAT/enhancer-binding protein (C/EBP)-α, and sterol regulatory element binding protein (SREBP)-1c in adipocyte-differentiated cells. PSE exerted greater effects on adipocyte differentiation and triglyceride content in 3T3-L1 cells under low-glucose conditions than under high-glucose conditions. These findings indicate that PSE enhances anaerobic glycolysis and inhibits adipocyte differentiation and fat accumulation in 3T3-L1 cells under glucose-restricted conditions.

Nutritional Composition, In Vitro Starch Digestibility and Antioxidant Activities of Composite Flour Made from Wheat and Mature, Unripe Pawpaw (Carica papaya) Fruit Flour.

Due to the rise in the number of people suffering from diet-related noncommunicable diseases, major scientific studies have recently been focused on the development of functional foods that are rich sources of resistant starch and bioactive compounds with health-promoting properties. The nutritional composition, in vitro starch digestibility, and antioxidant properties of composite flour derived from wheat and mature, unripe pawpaw fruit flour are all discussed in this study. The proximate composition, functional and pasting properties, in vitro starch digestibility, antioxidant activities and storage stability of the composite flours were determined. When compared to 100% wheat flour, the crude fiber, ash, water absorption capacity, swelling capacity, and bulk density of the composite flours increased by 40.5-63.3%, 209.7-318%, 2-109%, 3-66%, and 28-162%, respectively. Increased addition of mature, unripe pawpaw fruit flour to wheat flour resulted in a rise in the composite flour's TPC, ABTS, and ORAC values. Comparing the composite flour made with 50% mature, unripe pawpaw fruit flour to 100% wheat flour, the resistant starch and slowly digested starch rose by 2836% and 1321%, respectively. Additionally, compared to 100% wheat flour, the composite flours also demonstrated decreased fat acidity. It can be argued that the composite flour is a good source of resistant starch and bioactive ingredients that can be used in a variety of functional food products.

Nutrient enhancement potentials of moringa (Moringa oleifera), neem (Azadirachta indica), and pawpaw (Carica papaya) fortified composts in contaminated soils.

This study assessed the nutrient enhancement potentials of moringa (Moringa oleifera), neem (Azadirachta indica), and pawpaw (Carica papaya) fortified composts in contaminated soils. The composts were formulated from poultry manure; leaves of moringa, neem, and pawpaw; and sawdust for a period of 8 weeks. Contaminated soil samples were collected from a dumpsite in Abeokuta, Ogun State. The contaminated soils were treated with the stabilized composts for a period of 4 weeks. Castor oil plants were introduced to assess the nutrient quality of the composts. Soil and compost parameters (pH, electrical conductivity (EC), organic carbon (OC), total nitrogen (TN), C/N ratio, P, K, Na, Mg, and Ca) were determined using the standard procedures. Data collected were evaluated for simple descriptive and inferential statistics. Results showed non-significance (p > 0.05) of C/N ratios that ranged between 12.75 ± 2.43 and 12.96 ± 1.49. The pH values of moringa- and neem-fortified composts were slightly acidic, while the pawpaw-formulated compost was slightly alkaline. The levels of TN and OC were three times higher in moringa- and pawpaw-fortified composts than in the neem compost. Introduction of the composts to the contaminated soils decreased the soil pH but increased the nutrient quality parameters such as TN (33-50%), OC (56-77%), P (7-20%), Na (89-91%), K (12-25%), and Mg (10-13%). The three compost types increased the physiological properties of the castor oil plants. The study indicated the promising potentials of the three composts for nutrient enhancement of soil.

The growth-inhibitory effects of pawpaw (Asimina triloba [L.] Dunal) roots, twigs, leaves, and fruit against human gastric (AGS) and cervical (HeLa) cancer cells and their anti-inflammatory activities.

BACKGROUND: The pawpaw tree has several beneficial effects. However, no studies have been conducted to address the mechanisms underlying the cytotoxic effects of pawpaw extracts against cancer cells, and no study has investigated the anti-inflammatory effects. Hence, in this study, the growth-inhibitory effects of pawpaw (Asimina triloba [L.] Dunal) extracts against gastric (AGS) and cervical (HeLa) cancer cells and the inhibitory effects of pawpaw extracts against inflammatory factors (NO, TNF-α, IL-6, iNOS, and COX-2) were investigated. METHODS AND RESULTS: The viability of AGS and HeLa cells, the analysis of cell cycle, and the expression of apoptosis marker protein were determined using MTT assay, FACS, western blotting, and TUNEL assays. The inflammatory factors were determined using Griess method, ELISA assay kit, and RAW 264.7 cells. The IC50 values of twig and unripe fruit extracts for AGS cells were 82.01 and 100.61 µg/mL, respectively. For HeLa cells, pawpaw twig extracts exhibited the strongest ability to inhibit cervical cancer cell growth (IC50 = 97.73 µg/mL). Analysis of the cell cycle phase distribution and expression of the apoptosis regulatory proteins BCL-2, BAX, caspase-3, and PARP showed that pawpaw twig, root, and unripe fruit extracts induced Sub G1 cell cycle arrest and apoptosis of AGS and HeLa cells. In addition, the twig, root, and unripe fruit extracts of pawpaw effectively inhibited the inflammatory makers NO, TNF-α, IL-6, and iNOS. Particularly, the twig, root, and unripe fruit extracts at concentrations of 50 µg/mL exhibited > 50% inhibition of TNF-α. CONCLUSIONS: These findings indicate that pawpaw extracts are natural therapeutic agents that may be used for the prevention and treatment of gastric and cervical cancers, and encourage further studies on the anti-inflammatory potential of the pawpaw tree.

Influence of selected plant seeds on the performance, carcass characteristics, sensory evaluation, and economics of broiler chicken.

The immergence of antibiotic resistance, in livestock especially poultry, led to the ban of antibiotics as a growth promoter in some part of the world. This brought about the investigations into the development of various alternatives to antibiotics that will not compromise the integrity of poultry products for safe consumption. Therefore, this study examined the possible impacts of selected plants seeds (pawpaw, mustard, and black cumin) as feed additives on the performance, carcass characteristics, and sensory evaluation of broilers. A total of 180 day-old Arbor Acre Plus chicks were randomly assigned to five treatments of four replicates in a completely randomized design. The five treatments were three plant seed additives: pawpaw (PPS), mustard (MUS), and black cumin (BCS), treatment without additives (CON, i.e., no plants seeds/medications), and treatment with medications and antibiotics (ANT). During the feeding trials that lasted for 8 weeks, body weight gain, feed intake, and feed conversion ratio (FCR) were considered performance data. At the end of the feeding trials, two birds per replicate were slaughtered for carcass parameters and sensory evaluation. Data collected were subjected to analysis of variance. Mustard seed (Brassica juncea) significantly (P = 0.018) supported carcass growth. Further, the highest feed intake was obtained in MUS while the lowest was obtained in CON birds. The PPS had higher (P = 0.013) BWG than in other treatments while the lowest was obtained in CON. Values of FCR were lowest (P = 0.15) in PPS while the highest in CON birds. Furthermore, MUS and PPS had significantly (P = 0.018) and (P = 0.03) higher live weight than CON and ANT, while MUS had higher dressed weight percentage than CON and ANT birds. Broiler meat under diet supplemented with black cumin was relatively found to be most acceptable while meat under mustard seed was the least acceptable. In contrast, the average cost realized per bird was obtained in PPS while the lowest was in CON and ANT. However, broiler diet supplemented with BCS brings about a corresponding decrease in percentage feeding cost reduction among plant supplements.

Identification and analysis of cell wall glycan epitopes and polyphenol oxidase in pawpaw (Asimina triloba [L.] Dunal) fruit pulp as affected by high pressure processing and refrigerated storage.

This research explores the cell wall composition and polyphenol oxidase activity of two pawpaw (Asimina triloba) fruit varieties, Susquehanna and Green River Belle, that were subjected to high pressure processing and 45 days of refrigerated storage. We hypothesize that high pressure processing may inhibit enzymatic action responsible for pawpaw's deleterious postharvest tissue softening and browning. Glycome profiling uses mAb groupings that recognize 19 groups of glycan epitopes present in most major classes of cell wall glycans and was used to determine cell wall composition. Results show that both varieties have typical type I primary cell walls of flowering dicots. However, differences in the fine cell wall structure between the varieties can be inferred and the varieties behaved differently during refrigerated storage, likely indicating of a difference in cell wall-modifying enzymes present in the primary cell walls. High pressure processing treatment does not seem to be effective at eliminating polyphenol oxidase activity.

Neem, pawpaw and bamboo leaf meal dietary supplementation in broiler chickens: Effect on performance and health status.

The effect of the diet supplemented with leaf meals (LM) of neem (NLM), pawpaw (PLM), bamboo (BLM) and their composite leaf mix (CLM) on broiler chickens was assessed. Three hundred 1-day old broiler chickens were distributed to five diets: (control/no LM), (5 g/kg NLM), (5 g/kg PLM), (5 g/kg BLM) and (5 g/kg NLM+PLM+BLM 1:1:1). Body weight gain of birds fed BLM and CLM supplemented diets were similar but higher (p < 0.05) than those fed the control, NLM and PLM supplemented diets at day 42. The glucose, triglycerides, cholesterol, alanine aminotransferase and creatinine levels in LM supplemented diets were (p < 0.05) lower compared to the control. The superoxide dismutase, glutathione peroxidase and catalase were (p < 0.05) higher in LM supplemented diets compared to the control. The growth promoting potentials of bamboo leaf meal and the composite leaf mix can be harnessed for broiler chicken production. PRACTICAL APPLICATIONS: The use of herbs as the growth promoter is currently gaining research attention in most countries. In particular, herbal supplementation in poultry diets had been proposed as a means of enhancing the performance, stabilizing the physiological state, boosting immunity and antioxidative status in the birds. This study showed that improved body weight gain of broiler chickens at 42 days of age with attendant low serum glucose, triglycerides and cholesterol can be achieved when leaf meals from neem, pawpaw, bamboo and their composite mix were used as phyto-additives. The bamboo leaf meal and the composite leaf meal can be used to reduce the occurrence of arteriosclerosis which predisposes sudden death syndrome in well-grown and healthy broiler chickens. The procedures of raising broiler chickens to reach about 3 kg in less than 2 months impose a heavy burden on the heart, particularly overloading on the ventricular arteries leading to arteriosclerosis with age.

Phenolic Profiles, Antioxidant and Antimicrobial Activities of Pawpaw Pulp (Asimina triloba [L.] Dunal) at Different Ripening Stages.

In this study, the phenolic components, as well as the antioxidant and antimicrobial activities, of the ripe and unripe fruit of pawpaw (Asimina triloba [L.] Dunal) extracted using five different solvents (distilled water, 95% methanol, 80% methanol, 95% ethanol, and 80% ethanol) were analyzed. The total phenolic content and total flavonoid content were the highest in the 95% ethanol (149.50 mg CAE/g) and 80% ethanol (5.62 mg RE/g) extracts of the unripe fruit, respectively. Analysis of 17 phenolic compounds in pawpaw extracts revealed that epigallocatechin, epicatechin, and p-coumaric acid were the as major compounds, and the amounts of all components significantly decreased with the ripening (P < 0.05). In all antioxidant assays, the 95% ethanol extract of the unripe fruit showed the highest antioxidant activity (EC50 0.22 to 0.93 mg/mL). The pawpaw extracts were more sensitive against Corynebacterium xerosis and Clostridium perfringens. In particular, the 95% ethanol extract of the ripe fruit notably inhibited C. xerosis growth, with minimum inhibitory concentration of 1.56 mg/mL. These results showed that the unripe fruit of pawpaw has abundant phenolic compounds and superior antioxidant activity, and that the 95% ethanol extract of the ripe fruit shows strong inhibitory activity against various microorganisms. Therefore, pawpaw fruit can be utilized as an attractive source of nutrients and therapeutic agents. PRACTICAL APPLICATION: In this study, we identified that the unripe fruit of pawpaw is rich in phenolic compounds and shows strong antioxidant activities. The 95% ethanol extract of the ripe fruit showed strong high inhibitory effect against various microorganisms. These results suggest that pawpaw fruit can serve as a source of antioxidants and delay the aging process. In addition, the fruit could also potentially be utilized as a potential antimicrobial agent.

Isoquinoline alkaloids from Asimina triloba.

A new aporphine glycoside, (-)-anolobine-9-O-ß-D-glucopyranoside was isolated from the twigs of pawpaw (Asimina triloba) along with 7 known alkaloids including five aporphine alkaloids (anolobine, nornuciferine, norushinsunine, liriodenine, and lysicamine), a proaporhine alkaloid (stepharine), and a tetrahydrobenzylisoquinoline alkaloid (coclaurine). Among these compounds, nornuciferine, lysicamine, stepharine, and coclaurine are reported for the first time from this plant. The structure of the new compound was elucidated by spectroscopic methods, including 1 D, 2 D NMR, and HRESI-MS. The absolute configuration of compounds 1, 2, 7 and 8 was determined by CD experiment.

Targeted and non-targeted analysis of annonaceous alkaloids and acetogenins from Asimina and Annona species using UHPLC-QToF-MS.

In current work, targeted and non-targeted analysis of alkaloids and acetogenins from methanolic extracts of Asimina, Annona species and dietary supplements have been performed using UHPLC-QToF in positive ion mode. Thirty-five standard compounds (twelve alkaloids and twenty-three acetogenins) were used for the analysis. The fragment ions produced by collision induced dissociation (CID) revealed the characteristic cleavage and provided structural information. Aporphine alkaloids and acetogenins are the major groups found in Asimina and Annona species. An untargeted analysis based on high-resolution mass spectrometry was carried out to profile the alkaloids and acetogenins from Asimina species (As. triloba, As. parviflora). Magnoflorine, being a major alkaloid from twigs of As. triloba samples, was used as an example to discuss the fragmentation patterns. In (+)-ESI-MS, magnoflorine gave [M]+ ions at m/z 342.1705. The fragment ions at m/z 297.1127 [M-(CH3)2NH]+, 282.0886 [M-(CH3)3NH]+, 265.0865 [M-(CH3)2NH-CH3OH]+, 237.0916 [M-(CH3)2NH-CH3OH-CO]+, and 222.0681 [M-(CH3)2NH-CH3OH-CO-CH3]+ resulted from the [M]+ molecular ion. One dietary supplement claiming to contain paw paw (As. triloba) was also analyzed and showed a similar profile to twigs of As. triloba. A total of 131 compounds including standard compounds were identified from the different parts of As. triloba and As. parviflora samples. These compounds can be used to distinguish Asimina species. However, for definite identification of these unknown components, further investigation is required. This may provide a model for the rapid screening and structural characterization of bioactive constituents from plant extracts in a single analysis.

Antiangiogenic Activity and Chemical Derivatization of the Neurotoxic Acetogenin Annonacin Isolated from Asimina triloba.

Annonacin (1) was isolated from the North American pawpaw ( Asimina triloba), as reported earlier from these laboratories. Natural 1 was submitted to the rat aortic ring bioassay for evaluation of antiangiogenic activity and was found to inhibit microvessel growth (IC50 value of 3 µM). 4,10,15,20-Tetraazido derivatives of 1 were prepared by permesylation followed by azide displacement or by iodination followed by azide displacement. The tetraazide derived from mesylation/azidation was antiangiogenic, while that derived from iodination/azidation exhibited no appreciable activity. The membrane permeability of natural 1 was evaluated using the parallel artificial membrane permeability assay and was found to be marginally permeable as compared to several clinically relevant compounds.

Correlation Between Acetogenin Content and Antiproliferative Activity of Pawpaw (Asimina triloba [L.] Dunal) Fruit Pulp Grown in Korea.

Pawpaw (Asimina triloba [L.] Dunal) is widely cultivated in Korea for its fruit, which contains bioactive compounds, such as acetogenins. In this study, we investigated the acetogenin content and antiproliferative activity of pawpaw fruit pulp against various cancer cell lines and evaluated the relationship between these two variables at different maturation stages. Unripe fruit had higher antiproliferative activity than ripe fruit, and the activity level depended on acetogenin content. In addition, the presence of specific acetogenins was related to inhibition of certain cancer cell types. The unripe fruit methanol and ethanol extracts (URFM and URFE, respectively) that were rich in acetogenins strongly inhibited the growth of HT-1080, HeLa, and AGS cells by >50% at concentrations of less than 115 µg/mL. These findings indicate that URFM and URFE have therapeutic potential for the treatment of cancer, and our study establishes a basis for further mechanistic studies of the antiproliferative activity of pawpaw fruit. However, it is necessary to further study the anticancer activity of acetogenins from pawpaw fruit using in vivo activity approaches. PRACTICAL APPLICATION: Pawpaw (Asimina triloba) contains acetogenins that can inhibit the growth of cancer cells. In our study, we demonstrate that the antiproliferative activity is higher in unripe than in ripe fruit and depends on acetogenin content. Our results indicate that the extract of unripe pawpaw fruit has value not only as a functional food, but has therapeutic potential for the treatment of cancer as a naturally derived substance that may be less toxic than conventional chemotherapy drugs.

Valorization of underutilized North American pawpaw (Asimina triloba): investigation as a lipid oxidation inhibitor in turkey homogenate model system.

BACKGROUND: The objective of this study was to characterize the ability of extracts from nine varieties of pawpaw pulp standardized to the phenolics level of 0.1% grape seed extract (GSE) on inhibition of the formation of thiobarbituric reactive substances (TBARS) in a turkey model system. The antioxidant activity of the extracts was also determined using four common assays. RESULTS: Over the 240 min sampling time, the standardized pawpaw extracts from all nine varieties were as effective as GSE in inhibiting TBARS formation in turkey muscle homogenate compared to the untreated control. Extracts from all pawpaw varieties and GSE began to inhibit TBARS formation at 60 min of incubation, and by 240 min TBARS were reduced from 35 µmol malondialdehyde kg-1 tissue in the homogenate to which no antioxidant was added to 4-18 µmol malondialdehyde kg-1 tissue in the antioxidant-enriched extracts. There does not appear to be a clear relationship between inhibition of TBARS and any of the antioxidant capacity measurements (ORAC, DPPH inhibition, reducing potential as measured by FRAP assay, or pyrogallol red bleaching). CONCLUSION: The results of this research indicate that there is potential to add value to pawpaw as a functional food source of natural antioxidants, particularly in meat products. © 2017 Society of Chemical Industry.

Pollen-pistil interaction in pawpaw (Asimina triloba), the northernmost species of the mainly tropical family Annonaceae.

PREMISE OF THE STUDY: The pawpaw, Asimina triloba, is an underutilized fruit crop native to North America that belongs to the mainly tropical, early-divergent family Annonaceae. Asimina is the only genus within the Annonaceae with species adapted to cold climates. A thorough analysis of its reproductive biology, specifically pollen-pistil interaction during the progamic phase, is essential to understand both its adaptation to cold climates and how to optimize its fertilization and fruit set. METHODS: We characterized pollen-pistil interaction in Asimina triloba, including the floral cycle and anatomy, stigmatic receptivity, and the pollen tube pathway. We used a combination of histological, cytological, and immunolocalization approaches. KEY RESULTS: Asimina triloba has a gynoecium formed by plicate carpels with a short stylar canal. Unicellular papillae form a continuous tissue covered by a copious secretion from the stigma to the ovary, which is most prominent on the stigma surface where it forms an extragynoecial compitum. Compared to the stigmas of other species in the Annonaceae, the stigmas of A. triloba show a long stigmatic receptivity associated with a long flowering cycle. Stigmatic receptivity is concomitant with the secretion of cell-wall-related arabinogalactan proteins (AGPs). CONCLUSIONS: A long female phase with a long period of stigmatic receptivity is unusual among protogynous flowers of the magnoliid clade, suggesting a derived condition of A. triloba within the Annonaceae. This phase further correlates with the presence of cell-wall-related arabinogalactan proteins in the secretion, which may indicate the conservation of these glycoproteins during stigmatic receptivity and pollen tube growth in angiosperms.

Historical biogeography and ecological niche modelling of the Asimina-Disepalum clade (Annonaceae): role of ecological differentiation in Neotropical-Asian disjunctions and diversification in Asia.

BACKGROUND: The Asimina-Disepalum clade (Annonaceae subfam. Annonoideae tribe Annoneae) includes a major Neotropical-Asian biogeographical disjunction. We evaluate whether this disjunction can be explained by the Eocene boreotropics hypothesis, which relies on the existence of extensive boreotropical forests during the Late Palaeocene-Early Eocene thermal maximum (52-50 Ma), followed by disruption of boreotropical vegetation during post-Eocene cooling. Molecular dating using an uncorrelated relaxed molecular clock (UCLD) model with two fossil calibrations, ancestral range estimation, and ecological niche modelling across evolutionary time were performed. Our focus was the geographical origin of Disepalum and general biogeographic patterns within this genus. Comparison of ecological tolerance among extant species and niche reconstructions at ancestral nodes within the clade enabled insights in likely migration routes of lineages, as well as evaluating the role of bioclimatic ecological differentiation in the diversification of Disepalum within Southeast Asia. RESULTS: The inferred vicariance event associated with the Asimina-Disepalum disjunction is estimated to have originated ca. 40 Mya [95% highest posterior density (HPD): 44.3-35.5 Mya]. The Disepalum crown lineage is estimated to have originated ca. 9 Mya (95% HPD: 10.6-7.6), either in western Malesia and continental Southeast Asia, or exclusively in western Malesia. Ecological niche modelling shows that seasonality of temperature and precipitation are major contributors determining the geographical range of species. Ancestral niche modelling furthermore indicates that the ancestor of the Asimina-Disepalum clade likely had bioclimatic preferences close to conditions found in current tropical and subtropical climates across Asia, whereas the ancestors of the Asimina and Disepalum crown groups are projected onto the more subtropical and tropical regions, respectively. CONCLUSIONS: The vicariance event associated with the Neotropical-Asian disjunction within the Asimina-Disepalum clade likely coincided with climatic deterioration at the Eocene-Oligocene boundary. Although detrended component analyses (DCA) indicate that altitude and seasonality of temperature and precipitation have the greatest influence in determining the geographical range of species, isolation due to palaeogeographic and palaeoclimatic events appears to be of greater significance than climate niche differentiation in driving diversification in Disepalum.

Antioxidant Activities and Phenolic Compounds of Several Tissues of Pawpaw (Asimina triloba [L.] Dunal) Grown in Korea.

Pawpaw (Asimina triloba [L.] Dunal) possesses antioxidant compounds and strong inhibitors of cancer cells, and is widely cultivated in North America, Canada, and Korea. We analyzed the total phenolic and total flavonoid contents (TPC and TFC, respectively) of pawpaw plants grown in Korea and the antioxidant activities of their roots, twigs, leaves, and fruit with respect to 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis diammonium salt (ABTS) radical scavenging activity, ferrous (Fe2+ ) chelating ability, and nitrite scavenging activity. Pearson's correlation analyses revealed a linear correlation between TPC and antioxidant activities (r2 >0.69). Root methanol extracts had higher TPC and antioxidant activities than other extracts, which was also consistent with those from the phenolic compounds found in those extracts. Therefore, antioxidant activities seem to depend on the TPC of each pawpaw tissue and pawpaw roots might be useful as a natural source of natural antioxidants.

Unusual twig "twistiness" in pawpaw (Asimina triloba) provides biomechanical protection for distal foliage in high winds.

PREMISE OF STUDY: Deciduous woody species invest considerable resources in the growth of new foliage and distal stems. This new growth is at risk for mechanical damage from high winds and storms. Pawpaw has large leaves borne distally on thin twigs. Following a storm, pawpaw branches sometimes exhibit a persistent "flipped" orientation, slowly returning upright over 24 h. We investigated biomechanical properties of pawpaw twigs, comparing them to co-occurring species with similarly high leaf areas and loads, which do not exhibit this "flipping". Our goal was to determine biomechanical and structural properties in these species and how variation in form might relate to functional differences. METHODS: We measured flexural stiffness, torsional stiffness, and viscoelastic creep in pawpaw and co-occurring trees Liriodendron tulipifera and Carya cordiformis. We also recorded twig/foliage reconfiguration in high winds. We stained thin cross sections of distal twigs and recorded images using fluorescent light microscopy. KEY RESULTS: Flexural and torsional stiffness increased with twig radius in pawpaw and tulip tree, although torsional stiffness increased more slowly in pawpaw. Pawpaw had a high ratio of flexural to torsional stiffness (EI/GJ) across a range of twig radii and significant viscoelastic creep compared with the other species. CONCLUSIONS: Biomechanical data showed that pawpaw twigs were "twistier" than the comparison species, which were shown previously to alleviate drag-induced damage by reorienting petioles and leaves. Pawpaw has an unusual strategy of low torsional stiffness in twigs, allowing for reorientation of the entire distal appendage, likely minimizing drag-induced damage in storms.