Platform chemicals derived from lignocellulousic plant biomass are viewed as a sustainable replacement for crude oil based feed-stocks. Levulinic acid (LA) is one such biomass derived chemical that has been widely studied for further catalytic transformation to γ-valerolactone (GVL), an important 'green' fuel additive, solvent and fine chemical intermediate. Although the transformation of LA to GVL can be achieved using heterogeneous catalysis, homogeneous catalytic systems that operate under milder reactions, give high seletivities and can be recycled continue to attract much attention. A range of new homogeneous catalysts have now been demonstrated to efficiently convert LA to GVL, and to transform LA directly to other value added chemicals such as 1,4-pentanediol (1,4-PDO) and 2-methyltetrahydrofuran (2-MTHF). This mini review covers recent advances in the area of homogeneous catalysis for the conversion of levulinic acid and levulinic ester derivatives to GVL and chemicals beyond GVL.

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The methanol leaf extract of Jatropha tanjorensis was analyzed for its bioactive components, in-vitro antioxidant, antidepressant, anxiolytic and anti-inflammatory activities using established methods. The phytochemicals detected were saponins, tannins, terpenoids, phenolic compounds, alkaloids, flavonoids and eugenols. The total phenolic content (TPC) was 36.48 mgGAE/g, while the total flavonoid content (TFC) was 145.92 mgQE/g of the extract. 1, 1-diphenyl-2-picrylhydrazyl radical scavenging activity gave an IC50 of 185.02 and 5.15 µg/mL for the extract and ascorbic acid (standard), respectively. The 50% lethal dose (LD50) was greater than 5000 mg/kg, while graded doses of 50, 100 and 200 mg/kg of the plant extract relieved depression in mice to 93.3, 100 and 80.8%, respectively when compared with 10 mg/kg amitriptyline (positive control). A significant anxiety reduction, exemplified by a decrease in the frequency of head dip, was observed for animals administered with the plant extract compared with untreated control (p < 0.05). The reduction of formalin-induced paw edema was significant (p < 0.01) at 50 mg/kg of the plant extract, when compared with the control. The methanol extract of J. tanjorensis leaf is therefore a potential source of plant medicine with remarkable pharmacological activities. Keywords:    Jatropha tanjorensis; anxiolytic; antidepressant; anti-inflammatory; antioxidant; phytochemicals