Production of rohitukine in leaves and seeds of Dysoxylum binectariferum: an alternate renewable resource.

CONTEXT: Rohitukine is an important precursor for the synthesis of potential anticancer drugs flavopiridol (Sanofi-Aventis) and P-276-00 (Piramal Healthcare Limited, Mumbai, India). Trunk bark of Dysoxylum binectariferum (Roxb.) Hook. f. ex Bedd. (Meliaceae) is the widely used source for isolation of rohitukine. However, removal of trunk bark threatens the survival of the tree. OBJECTIVE: To investigate the amount of rohitukine accumulated in other tissues of D. binectariferum. MATERIALS AND METHODS: Rohitukine standard was isolated from leaves of D. binectariferum. Its purity was ascertained using HR-MS and NMR. Crude extracts were prepared from different tissues of D. binectariferum. Rohitukine content in all the tissues was quantified by HPLC. RESULTS: Rohitukine accumulates in a significant amount in seeds, trunk bark, leaves, twigs, and fruits of D. binectariferum. Seeds have the highest rohitukine content (2.42%, dry weight) followed by trunk bark (1.34%, dry weight), leaves (1.064%, dry weight), twigs (0.844% dry weight), and fruits (0.4559% dry weight). DISCUSSION AND CONCLUSION: Seeds and leaves of D. binectariferum could be used as alternate renewable sources for isolation of rohitukine.

Assessment of Biological Activities of Fungal Endophytes Derived Bioactive Compounds Isolated from Amoora rohituka.

Fungal endophytes have remarkable potential to produce bioactive compounds with numerous pharmacological significance that are used in various disease management and human welfare. In the current study, a total of eight fungal endophytes were isolated from the leaf tissue of Amoora rohituka, and out of which ethyl acetate (EA) extract of Penicillium oxalicum was found to exhibit potential antioxidant activity against DPPH, nitric oxide, superoxide anion and hydroxyl free radicals with EC50 values of 178.30 ± 1.446, 75.79 ± 0.692, 169.28 ± 0.402 and 126.12 ± 0.636 µg/mL, respectively. The significant antioxidant activity of EA extract of P. oxalicum is validated through highest phenolic and flavonoid content, and the presence of unique bioactive components observed through high-performance thin layer chromatography (HPTLC) fingerprinting. Moreover, EA extract of P. oxalicum also displayed substantial anti-proliferative activity with IC50 values of 56.81 ± 0.617, 37.24 ± 1.26 and 260.627 ± 5.415 µg/mL against three cancer cells HuT-78, MDA-MB-231 and MCF-7, respectively. Furthermore, comparative HPTLC fingerprint analysis and antioxidant activity of P. oxalicum revealed that fungal endophyte P. oxalicum produces bioactive compounds in a host-dependent manner. Therefore, the present study signifies that fungal endophyte P. oxalicum associated with the leaf of A. rohituka could be a potential source of bioactive compounds with antioxidant and anticancer activity.

Rohitukine, a chromone alkaloid and a precursor of flavopiridol, is produced by endophytic fungi isolated from Dysoxylum binectariferum Hook.f and Amoora rohituka (Roxb).Wight & Arn.

Rohitukine, a chromone alkaloid, has gained considerable international attention in recent years because of its novel semi-synthetic derivative, flavopiridol and P-276-00. Both these molecules are in advanced stages of clinical development and trial for cancer treatment. Recently, flavopiridol was approved as an orphan drug for treatment of chronic lymphocytic leukemia cancer. The natural occurrence of rohitukine is restricted to only four plant species, Amoora rohituka and Dysoxylum binectariferum (both from the Meliaceae family) and from Schumanniophyton magnificum and Schumanniophyton problematicum (both from the Rubiaceae family). Recently, an endophytic fungi isolated from D. binectariferum was reported to produce rohitukine in culture. In this study, we report the production of rohitukine and its subsequent attenuation by endophytic fungi, Fusarium oxysporum (MTCC-11383), Fusarium oxysporum (MTCC-11384) and Fusarium solani (MTCC-11385), all isolated from D. binectariferum and Gibberella fujikuroi (MTCC-11382) isolated from Amoora rohituka. The fungal rohitukine which was analyzed by HPLC, LC-MS and LC-MS/MS was identical to reference rohitukine and that produced by the plant. The rohitukine content in the mycelial samples ranged from 192.78µg to 359.55µg100g(-1) of dry weight of and in broth it ranged from 14.10 to 71.90µg100ml(-1). In all the fungal cultures, the production declined from first to fourth sub-culture. Studies are underway to unravel the mechanism by which the fungi produce the host metabolite in culture.