Forest biorefinery: Potential of poplar phytochemicals as value-added co-products.

The global forestry industry after experiencing a market downturn during the past decade has now aimed its vision towards the integrated biorefinery. New business models and strategies are constantly being explored to re-invent the global wood and pulp/paper industry through sustainable resource exploitation. The goal is to produce diversified, innovative and revenue generating product lines using on-site bioresources (wood and tree residues). The most popular product lines are generally produced from wood fibers (biofuels, pulp/paper, biomaterials, and bio/chemicals). However, the bark and other tree residues like foliage that constitute forest wastes, still remain largely an underexploited resource from which extractives and phytochemicals can be harnessed as by-products (biopharmaceuticals, food additives and nutraceuticals, biopesticides, cosmetics). Commercially, Populus (poplar) tree species including hybrid varieties are cultivated as a fast growing bioenergy crop, but can also be utilized to produce bio-based chemicals. This review identifies and underlines the potential of natural products (phytochemicals) from Populus species that could lead to new business ventures in biorefineries and contribute to the bioeconomy. In brief, this review highlights the importance of by-products/co-products in forest industries, methods that can be employed to extract and purify poplar phytochemicals, the potential pharmaceutical and other uses of >160 phytochemicals identified from poplar species - their chemical structures, properties and bioactivities, the challenges and limitations of utilizing poplar phytochemicals, and potential commercial opportunities. Finally, the overall discussion and conclusion are made considering the recent biotechnological advances in phytochemical research to indicate the areas for future commercial applications from poplar tree species.

Occular and dermal toxicity of Jatropha curcas phorbol esters.

Jatropha curcas seeds are a promising feedstock for biodiesel production. However, Jatropha seed oil and other plant parts are toxic due to the presence of phorbol esters (PEs). The ever-increasing cultivation of toxic genotype of J. curcas runs the risk of increased human exposure to Jatropha products. In the present study, effects of J. curcas oil (from both toxic and nontoxic genotypes), purified PEs-rich extract and purified PEs (factors C1, C2, C(3mixture), (C4+C5)) on reconstituted human epithelium (RHE) and human corneal epithelium (HCE) were evaluated in vitro. The PEs were purified from toxic Jatropha oil. In both RHE and HCE, the topical application of PEs containing samples produced severe cellular alterations such as marked oedema, presence of less viable cell layers, necrosis and/or partial tissue disintegration in epithelium and increased inflammatory response (interleukin-1α and prostaglandin E2). When compared to toxic oil, histological alterations and inflammatory response were less evident (P<0.05) in nontoxic oil indicating the severity of toxicity was due to PEs. Conclusively, topical applications of Jatropha PEs are toxic towards RHE and HCE models, which represents dermal and occular toxicity respectively. Data obtained from this study would aid in the development of safety procedures for Jatropha biodiesel industries. It is advised to use protective gloves and glasses when handling PEs containing Jatropha products.

Pharmaceutical potential of phorbol esters from Jatropha curcas oil.

Phorbol esters (PEs) are diterpenes present in Jatropha curcas L. seeds and have a myriad of biological activities. Since PEs are toxic, they are considered to be futile in Jatropha-based biodiesel production chain. In the present study, the extracted PEs from Jatropha oil were used as a starting material to synthesise pharmacologically important compound, prostratin. The prostratin synthesised from Jatropha showed identical mass with that of the reference standard prostratin, as determined by Nano-LC-ESI-MS/MS. Considering the rapid growth in Jatropha biodiesel industry, potential exists to harness large amount of PEs which can be further utilised to synthesise prostratin as a value added product.

Isolation, stability and bioactivity of Jatropha curcas phorbol esters.

Jatropha curcas seed oil, which can be utilized for biodiesel production upon transesterification, is also rich in phorbol esters (PEs). In this study, PEs from J. curcas oil (Jatropha factors C1 and C2 (purified to homogeneity), Jatropha factors C3 and (C4+C5) (obtained as mixtures) and PE-rich extract (containing all the above stated Jatropha factors) were investigated. The concentrations of Jatropha PEs were expressed equivalent to Jatropha factor C1. In the snail (Physa fontinalis) bioassay, the order of potency (EC50, µg/L) was: PE-rich extract

Activities of Jatropha curcas phorbol esters in various bioassays.

Jatropha curcas seeds contain 30-35% oil, which can be converted to high quality biodiesel. However, Jatropha oil is toxic, ascribed to the presence of phorbol esters (PEs). In this study, isolated phorbol ester rich fraction (PEEF) was used to evaluate the activity of PEs using three aquatic species based bioassays (snail (Physa fontinalis), brine shrimp (Artemeia salina), daphnia (Daphnia magna)) and microorganisms. In all the bioassays tested, increase in concentration of PEs increased mortality with an EC(50) (48 h) of 0.33, 26.48 and 0.95 mg L(-1) PEs for snail, artemia and daphnia, respectively. The sensitivity of various microorganisms for PEs was also tested. Among the bacterial species tested, Streptococcus pyogenes and Proteus mirabilis were highly susceptible with a minimum inhibitory concentration (MIC) of 215 mg L(-1) PEs; and Pseudomonas putida were also sensitive with MIC of 251 mg L(-1) PEs. Similarly, Fusarium species of fungi exhibited EC(50) of 58 mg L(-1) PEs, while Aspergillus niger and Curvularia lunata had EC(50) of 70 mg L(-1). The snail bioassay was most sensitive with 100% snail mortality at 1 µg of PEs mL(-1). In conclusion, snail bioassay could be used to monitor PEs in Jatropha derived products such as oil, biodiesel, fatty acid distillate, kernel meal, cake, glycerol or for contamination in soil or other environmental matrices. In addition, PEs with molluscicidal/antimicrobial activities could be utilized for agricultural and pharmaceutical applications.

Localisation of antinutrients and qualitative identification of toxic components in Jatropha curcas seed.

BACKGROUND: Jatropha curcas seed oil is a promising feedstock for biodiesel production. The seeds contain major toxic (phorbol esters, PEs) and antinutritional (phytate and trypsin inhibitor) factors. In the present study the localisation of antinutrients and a rapid qualitative method for detecting the presence of PEs were investigated. RESULTS: Kernels were separated into cotyledon, hypocotyl, kernel coat and endosperm. The majority of phytate (96.5%), trypsin inhibitor (95.3%) and PEs (85.7%) were localised in the endosperm. Based on PEs, a qualitative method was developed to differentiate between toxic and non-toxic Jatropha genotypes. In this method, PEs were easily detected by passing methanol extracts of kernels (Jatropha toxic and non-toxic genotypes) through a solid phase extraction (SPE) column and measuring the absorption of the resulting eluates at 280 nm. For raw kernels, SPE eluates with absorbance ≥ 0.056 were considered as toxic and those with absorbance ≤0.032 as non-toxic. For defatted kernel meals, SPE eluates with absorbance ≥ 0.059 were considered as toxic and those with absorbance ≤0.043 as non-toxic. CONCLUSION: The majority of antinutrients/toxic compounds are localised in the endosperm of the kernel. The qualitative method developed for rapid identification of toxic PEs could be useful in screening the toxicity of Jatropha-based products in the biodiesel industry. Further confirmation of PEs should be established by high-performance liquid chromatography.

Isolation of phytate from Jatropha curcas kernel meal and effects of isolated phytate on growth, digestive physiology and metabolic changes in Nile tilapia (Oreochromis niloticus L.).

Jatropha curcas seeds are rich in oil and protein. The oil is used for biodiesel production. The defatted Jatropha kernel meal obtained after oil extraction is rich in protein (58-66%) and phytate (9-11%). The phytate rich fraction was isolated from defatted kernel meal using organic solvents (acetone and carbon tetracholride). It had 66% phytate and 22% crude protein. The fingerlings (n=50, 16.2 ± 0.64 g) were randomly distributed into five groups containing 10 replicates and fed iso-nitrogenous diets (crude protein 36%): control diet containing casein and gelatin as proteins; control diet containing 1.5% and 3% Jatropha phytate (PWP(1.5) and PWP(3), respectively); and control diet containing 1.5% and 3% Jatropha phytate supplemented with phytase (1500 FTU/kg) (PWP(1.5+Phytase) and PWP(3+Phytase), respectively). Significantly lower (P<0.05) growth and feed utilization in PWP(1.5) and PWP(3) groups than for control and both phytase containing groups were observed; whereas feed gain ratio exhibited opposite trend. Protein and lipid digestibilities of the diets, amylase and protease enzyme activities in the intestine were significantly higher (P<0.05) in PWP(1.5+Phytase) and PWP(3+Phytase) groups than for PWP(1.5) and PWP(3) groups. Lowest red blood cell counts, and hemoglobin and hematocrit concentrations were observed in PWP(3) group which were not statistically different to those for PWP(1.5) group, but were significantly (P<0.05) lower than those for all other groups. Highest albumin, globulin and total protein concentrations were observed in PP(3+Phytase) group and lowest in PWP(1.5) group; and values for the latter were statistically similar to those for control group. Calcium, phosphorus and glucose concentrations in blood and cholesterol concentration in plasma were significantly lower (P<0.05) in the phytate enriched groups compared with control and phytase treated groups (PP(1.5+Phytase) and PP(3+Phytase)). Higher (P<0.05) alkaline phosphatase activity was observed in phytase supplemented groups compared with that in non-supplemented groups which (PP(1.5+Phytase)) was statistically similar to that in control group, whereas alanine transaminase activity in blood exhibited opposite trend. In conclusion, Jatropha phytate present in DJKM is an antinutrient and addition of phytase in the diet containing DJKM is recommended.

Jatropha toxicity--a review.

Jatropha is a nonedible oil seed plant belonging to Euphorbiaceae family. Global awareness of sustainable and alternative energy resources has propelled research on Jatropha oil as a feedstock for biodiesel production. During the past two decades, several cultivation projects were undertaken to produce Jatropha oil. In future, the increased cultivation of toxic Jatropha plants and utilization of its agro-industrial by-products may raise the frequency of contact with humans, animals, and other organisms. An attempt was thus made to present known information on toxicity of Jatropha plants. The toxicity of Jatropha plant extracts from fruit, seed, oil, roots, latex, bark, and leaf to a number of species, from microorganisms to higher animals, is well established. Broadly, these extracts possess moluscicidal, piscicidal, insecticidal, rodenticidal, antimicrobial, and cytotoxic properties, and exert adverse effects on animals including rats, poultry, and ruminants. The toxicity attributed to these seeds due to their accidental consumption by children is also well documented. An attempt was also made to identify areas that need further study. The information provided in this review may aid in enhancing awareness in agroindustries involved in the cultivation, harvesting, and utilization of Jatropha plants and its products with respect to the potential toxicity of Jatropha, and consequently in application and enforcement of occupational safety measures. Data on the wide range of bioactivities of Jatropha and its products were collated and it is hoped will create new avenues for exploiting these chemicals by the phamaceutical industry to develop chemotherapeutic agents.

Biodegradation of Jatropha curcas phorbol esters in soil.

BACKGROUND: Jatropha curcas seed cake is generated as a by-product during biodiesel production. Seed cake containing toxic phorbol esters (PEs) is currently used as a fertiliser and thus it is of eco-toxicological concern. In the present study the fate of PEs in soil was studied. RESULTS: Two approaches for the incorporation of PEs in soil were used. In the first, silica was bound to PEs, and in the second, seedcake was used. At day 0, the concentration of PEs in soil was 2.6 and 0.37 mg g(-1) for approach 1 and 2 respectively. PEs from silica bound PEs were completely degraded after 19, 12, 12 days (at 130 g kg(-1) moisture) and after 17, 9, 9 days (at 230 g kg(-1) moisture) at room temperature, 32 degrees C and 42 degrees C respectively. Similarly at these temperatures PEs from seed cake were degraded after 21, 17 and 17 days (at 130 g kg(-1) moisture) and after 23, 17, and 15 days (at 230 g kg(-1) moisture). Increase in temperature and moisture increased rate of PEs degradation. Using the snail (Physa fontinalis) bioassay, mortality by PE-amended soil extracts decreased with the decrease in PE concentration in soil. CONCLUSION: Jatropha PEs are biodegradable. The degraded products are innocuous.

Nutritional, biochemical, and pharmaceutical potential of proteins and peptides from jatropha: review.

Increased bioenergy consciousness and high demand for animal products have propelled the search for alternative resources that could meet the dual demands. Jatropha seeds have potential to fit these roles in view of their multipurpose uses, broad climatic adaptability features, and high oil and protein contents. During the past five years many large-scale cultivation projects have been undertaken to produce jatropha seed oil as a feedstock for the biodiesel industry. The present review aims at providing biological significance of jatropha proteins and peptides along with their nutritional and therapeutic applications. The nutritional qualities of the kernel meal and protein concentrates or isolates prepared from seed cake are presented, enabling their efficient use in animal nutrition. In addition, (a) biologically active proteins involved in plant protection, for example, aquaporin and betaine aldehyde dehydrogenase, which have roles in drought resistance, and beta-glucanase, which has antifungal activity, as well as those having pharmaceutical properties, and (b) cyclic peptides with various biological activities such as antiproliferative, immunomodulatory, antifungal, and antimalarial activity are discussed. It is expected that the information collated will open avenues for new applications of proteins present in jatropha plant, thereby contributing to enhance the financial viability and sustainability of a jatropha-based biodiesel industry.

Toxicity of Jatropha curcas phorbol esters in mice.

Phorbol esters are the main toxins in Jatropha curcas seed and oil. The aim of this study was to assess the acute toxicity of phorbol esters given by intragastric administration and to determine the LD50 for Swiss Hauschka mice. The LD50 and 95% confidence limits for male mice were 27.34 mg/kg body mass and 24.90-29.89 mg/kg body mass; and the LD5 and LD95 were 18.87 and 39.62 mg/kg body mass, respectively. The regression equations between the probits of mortalities (Y) and the log of doses (D) was Y=-9.67+10.21 log (D). Histopathological studies on the organs from the dead mice showed: (1) no significant abnormal changes in the organs at the lowest dose (21.26 mg/kg body mass) studied, (2) prominent lesions mainly found in lung and kidney, with diffused haemorrhages in lung, and glomerular sclerosis and atrophy in kidney at doses > or = 32.40 mg/kg body mass, and (3) multiple abruption of cardiac muscle fibres and anachromasis of cortical neurons at the highest dose of 36.00 mg/kg body mass. The results obtained would aid in developing safety measures for the Jatropha based biofuel industry and in exploiting the pharmaceutical and agricultural applications of phorbol esters.