Phytochemical profile and antioxidation activity of annona fruit and its effect on lymphoma cell proliferation.

Cancers of the lymphatic system are broadly classified into Hodgkin and non-Hodgkin types. Although lymphomas can be effectively treated with chemotherapy, this approach is associated with the risk of adverse side effects. High intake of certain vegetables and fruits is associated with a reduced risk of cancer development. We hypothesized that Annona fruit, which is rich in fibers and phytochemicals that are known to possess anticancer properties, can be effective in inhibiting lymphoma growth. The Annona fruit's fractions were extracted with water, methanol, or chloroform and then assayed for total phenolic, flavonoids, and tannins content; antioxidation activities; and inhibition of in vitro cell proliferation using the Ramos-1 lymphoma cells. The methanol fractions contained the highest phenolics, flavonoids, and tannins content, and antioxidation activity. However, the methanol extracts of skin, pulp, and seeds had a moderate whereas the chloroform extracts of pulp and seeds had strong effects on Ramos-1 cell proliferation. Our findings suggest that Annona fruits may be effective in the prevention or treatment of lymphoma.

KNAT6: an Arabidopsis homeobox gene involved in meristem activity and organ separation.

The homeobox gene family plays a crucial role during the development of multicellular organisms. The KNOTTED-like genes from Arabidopsis thaliana (KNAT6 and KNAT2) are close relatives of the meristematic genes SHOOT MERISTEMLESS (STM) and BREVIPEDICELLUS, but their function is not currently known. To investigate their role, we identified null alleles of KNAT6 and KNAT2. We demonstrate that KNAT6 contributes redundantly with STM to the maintenance of the shoot apical meristem (SAM) and organ separation. Consistent with this role, the expression domain of KNAT6 in the SAM marks the boundaries between the SAM and cotyledons. The lack of meristematic activity in the knat6 stm-2 double mutant and the fusion of cotyledons were linked to the modulation of CUP-SHAPED COTYLEDON (CUC) activity. During embryogenesis, KNAT6 is expressed later than STM and CUC. In agreement with this fact, CUC1 and CUC2 were redundantly required for KNAT6 expression. These data provide the basis for a model in which KNAT6 contributes to SAM maintenance and boundary establishment in the embryo via the STM/CUC pathway. KNAT2, although the closest related member of the family to KNAT6, did not have such a function.