Extracts affecting mitotic division in root-tip meristematic cells

Abstract

Some species of Psychotria (Rubiaceae) are important in herbal medicine, where their extracts are used internally for infections of the female reproductive system, bronchitis, gastrointestinal disturbances, skin irritations, tumors, ulcers, and eye disturbances. The antiproliferative and genotoxic effects of Psychotria myriantha Mull. Arg. and P. leiocarpa Cham. et Schlecht infusions on the Allium cepa L. cell cycle were evaluated. The teas were prepared by infusing the leaves in distilled water, in two concentrations: 1.13 mg/mL and 6.78 mg/mL. Three groups of four bulbs were used for each Psychotria species. After the bulbs rooted in distilled water, they were transferred to the teas for 24 hours, except for the control that stayed in water. The rootlets were then collected, fixed in ethanol-acetic acid (3:1) for 24 hours, and stored in 70% ethanol. For each group of bulbs, 4000 cells were analyzed, calculating the mitotic indexes, submitting them to statistic analysis, using the χ 2 test (p = 0.05). The results showed a decrease in mitotic index with an increase in tea concentration in both species. In P. leiocarpa, the mitotic index values differed significantly between the control and concentration of 6.78 mg/mL (χ 2 = 9.863). For P. myriantha, the values referring to the mitotic index differed greatly between the control and the treatments (χ 2 = 124.8). With this study, it was determined that P. myriantha and P. leiocarpa infusions possess antiproliferative effects on the A. cepa cell cycle, and teas of P. myriantha also have genotoxic activity.

Cytogenotoxicity of Cymbopogon citratus (DC) Stapf (lemon grass) aqueous extracts in vegetal test systems

“…These aspects were observed mainly in the lem4 treatment, where the mitotic index showed a significant decrease in relation to the control. Similar results were observed in previous studies and cell death was the major depressor of the mitotic index (Çelik and Aslantürk 2006, Campos et al 2008, Lubini et al 2008.…”

“…This alteration in chromosome morphology reinforces the toxicity potentiality of some doses of C. citrates extracts, once these alteration evidences the toxic effect on the chromatin allowed by cell death (Campos et al 2008, Lubini et al 2008.…”

“…Among the various available methodologies, tests that use plant roots are extremely useful in biological assays, relatively inexpensive and can easily be handled. In addition, plant cytotoxic bioassays have a good correlation with mammalian test systems (Fiskesjö 1985, Jovtchev et al 2002, Yi and Meng 2003, Çelik and Aslantürk 2006, Lubini et al 2008.…”

“…Thus, after an inadequate use, several disorders may occur, from intoxications to mutation events in somatic and germinative tissue, and it can lead to the development of somatic diseases, teratogenic effects and inherited genetic damages (Çelik and Aslantürk 2006, Pugliesi et al 2007, Lubini et al 2008. Most carcinogens, for example, trigger their tumorigenic activity by the interaction of natural inductors of mutations with the DNA, leading to permanent genetic lesions, which are expressed as genetic mutations or chromosomal aberrations involving the cell cycle (Bronzetti et al 1996, Gonzalgo and Jones 1997, Nunes and Carvalho 2003.…”

Investigation on the effects of guava (Psidium guajava L.) infusions on germination, root tips and meristematic cells of Latuca sativa

“…The cytotoxic level of the agent can be determined both by the increase as well as by the decrease in MI (Lubini et al 2008). The first could be a consequence of disordered cell proliferation, potentially leading to the formation of tumors (Campos et al 2008).…”