Dominique Lacan

High levels of antioxidant enzymes correlate with delayed senescence in nonnetted muskmelon fruits

Abstract. We investigated the senescence process in two nonnetted muskmelon (Cucumis melo L.)␣varieties␣Clipper and Jerac differing in their storage life. Our results indicate that senescence in Jerac (the short-storage-life variety, less than 7 d) is the result of lipid peroxidation by free radicals, membrane phospholipid breakdown, and a drop in the level of antioxidants, resulting in increased membrane leakiness. By contrast, evidence is presented that the high levels of two enzymes implicated in antioxidative defence, superoxide dismutase (SOD) and catalase, combined with changes in the three different classes of SOD during the storage stage, are involved in delaying the senescence process in Clipper and this could explain, at least, to some extent, the long storage life of Clipper (longer than 14 d).

Physiological effects of temporary immersion on Hevea brasiliensis callus

In vitro culture by temporary immersion generates potentially stressful conditions for explants that may differ from those associated with classic methods. In order to evaluate the effects of these conditions on physiological changes in explants, different parameters of metabolic activity were investigated for a friable embryogenic callus of Hevea brasiliensis (Müll. Arg.), in response to 1 min, and 1, 12 and 24 h per day of immersion, using semi-solid and agitated liquid media as controls. The relative growth rate of the callus was not significantly different for the 1 min immersion treatment and the controls, but it decreased by about 60% for the 1-, 12- and 24-h immersion treatments. During the immersed stage, the rate of respiration of the callus was comparable for all the treatments. However, during the emersed stage, the respiration rate increased by 140 and 164% for the 12- and 24-h immersion treatments, respectively. Meanwhile, the total adenylate nucleotide concentration and the ratio of ATP/ADP remained almost constant, or even decreased. The adenylate energy charge was comparable for all the treatments, averaging 0.88. The superoxide dismutase activity and the lipid peroxidation increased with the immersion duration, and were significantly higher for the 12- and 24-h immersion treatments than for controls. However, after 24 h in emersed stage, there was no lipid peroxidation, regardless of previous immersion duration. It appears from these results that the immersed stage induced a substantial oxidative stress, which was not associated with the callus immersion per se.

Étude clinique d’une SuperOxide Dismutase de melon naturelle et bioactive (SOD B Dimpless®) sur la cellulite

RésuméUne étude clinique, randomisée en double aveugle contre placebo, a été conduite sur 41 femmes ayant de la cellulite, âgées de 31 à 50 ans. 21 d’entre elles ont été supplémentées oralement avec SOD B Dimpless®, un jus de melon séché hautement concentré en SuperOxyde Dismutase (SOD), à 40 mg par jour (480 IU SOD) pendant 56 jours consécutifs. La cellulite a été mesurée par l’évaluation visuelle des capitons graisseux sur le ventre et les cuisses, à l’aide d’une échelle linéaire. La supplémentation orale avec SOD B Dimpless® a significativement réduit la cellulite sur les cuisses en comparaison avec le groupe placebo après 28 jours. Cette réduction est amplifiée après 56 jours de supplémentation. Le mécanisme d’action pourrait impliquer l’induction de l’expression des enzymes antioxydantes endogènes, conduisant à l’inhibition de la fibrose et à la stimulation de la lipolyse. D’autres investigations sont nécessaires afin de confirmer le mode d’action de SOD B Dimpless® contre la cellulite.AbstractA randomized, double blind, placebo controlled clinical study was conducted on 41 women with cellulite aged between 31 and 50 years old. 21 of these were orally supplemented with SOD B Dimpless®, a natural dry melon juice highly concentrated in SuperOxide Dismutase (SOD) at 40 mg per day (480 IU SOD), during 56 consecutive days. Cellulite was measured visually by scoring fat nodes on stomach and thighs, according to a linear scale. The oral supplementation with SOD B Dimpless® significantly reduced cellulite on thighs compared to the placebo after 28 days. This reduction is amplified after 56 days of supplementation. The mechanism of action may involve the induction of endogenous antioxidant enzymes expression, leading to the inhibition of fibrosis and the stimulation of lipolysis. Further investigations are necessary to document the way of action of SOD B Dimpless® against cellulite.