Scalable synthesis of two-dimensional nano-sheet materials with chlorophyll extracts: enhancing the hydrogen evolution reaction

Developing strategies for preparing high-quality atomically thin two-dimensional (2D) nanomaterials is still an unaccomplished goal.

Efek pemberian ekstrak klorofil daun pepaya (carica papaya, linn.) terhadap kadar ast dan alt serum

Background: Pharmacological therapy is one of the therapy modalities which carries the hepatic injury as one of its side effects. Nowadays, curcuma tablets has become choice of hepatoprotector. Other substance which has the possibilities of hepatoprotection activities is chlorophyll. The study is aimed to investigate the effect of papaya leaves chlorophyll extracts towards the serum AST and serum ALT levels on high-dose-paracetamol-induced Wistar rats. Materials and methods: This was an experimental study applying pretest-posttest controlled group design. Twenty eight Wistar rats 8-12 weeks age and weighted 185-220 grams assigned into four groups, namely group I (control), group II (paracetamol 750 mg/kg bw + no hepatoprotector agent), group III (paracetamol 750 mg/kg bw + curcuma 100 mg/kg bw), and group IV (paracetamol 750 mg/kg bw + papaya leaves chlorophyll extracts 300 mg/kg bw). The hepatoprotector agents were administered for a week, while the high dose paracetamol was administered for three consecutive days (day 5, 6, and 7). The pretest samples were drawn on the fifth day before the administration of high dose paracetamol, and the posttest samples were drawn on eightth day. Results: There were no difference among four groups on serum AST and serum ALT levels before the administration of high dose paracetamol, p=0.522 dan p=0.682, respectively. After the administration of high dose paracetamol, there were differences among four groups on both variables, both p=0.000. The post-hoc test showed that differences happened on all four groups (p<0.05).Conclusion: Chlorophyll extract of papaya leaves can inhibit liver injury on high-dose-paracetamol-induced-Wistar rats.

Photosensitization of albino rats fed on lucerne-proetin concentrate

1. The photosensitizing effect of leaf-protein concentrate (LPC) prepared from lucerne (Medicago sativa) was demonstrated when it was included in the diet of albino rats at concentrations between 40 and 480 g/kg diet.2. Skin lesions of varying severity up to the sloughing of ears and tails occurred when such rats were illuminated with natural daylight through window-glass or with simulated daylight from a bank of lamps having emission maxima at 410, 437 and 660 nm and with approximately 4% of the energy of summer sunlight.3. Protein concentrates prepared from ryegrass (Lolium multiforum) and a crude chlorophyll extract of spinach (Spinacea oleracea) did not cause these effects.4. Extracts from blood plasma and livers of rats given lucerne LPC contained pheophorbide-a and two other unidentified green pigments, but no detectable phylloerythrin or chlorophyll. Extracts from the blood of rats given ryegrass LPC had no detectable pheophorbide or other chlorophyll-derived pigments.5. The lucerne LPC given to the rats contained relatively large amounts of pheophorbide-a among a variety of pigments. The ryegrass LPC and the spinach extracts had only small amounts of this pigment relative to the other chlorophyll-type pigments.6. These findings indicate that pheophorbide-a and related pigments are the agents responsible for the photosensitization of the rats. Possible explanations of their presence in lucerne LPC are discussed.

Formaldehyde as an oxidation product of chlorophyll extracts

Of recent years the action on carbon dioxide of chlorophyll in vitro has assumed some importance as possibly throwing light on the nature of the photo-synthetic process of green plants. Thus Usher and Priestley have stated that films of extracted chlorophyll in the presence of moist air and carbon dioxide produce formaldehyde and hydrogen peroxide under the influence of light. The earlier work of these authors has been adversely commented upon by several writers, notably by Ewart, to whose criticisms Usher and Priestley have replied with a number of additional experiments and arguments, referring also to the work of Schryver, subsequent to that of Ewart, as affording strong confirmation of their views as far as the synthesis of the aldehyde is concerned. The facts set forth in the present paper came to light during an attempt to confirm and extend the observations of Usher and Priestley and of Schryver. Grass was extracted with alcohol, usually in the cold and in the presence of calcium carbonate. In some experiments the alcoholic liquid was evaporated to dryness under reduced pressure and the residue extracted with ether; in others a solution of chlorophyll in light petroleum was obtained by shaking the alcoholic solution with that liquid. The method of experiment was based upon that described by Schryver, the ether or petroleum extract being allowed to evaporate on glass plates and exposed to light under the various conditions to be mentioned below. As was the case in the later experiments of Usher and Priestley themselves, the test which has been relied upon for the detection of formaldehyde is the very delicate one devised by Schryver, who has found that the reaction is not given by such other members of the series as have been examined up to the present. It has been assumed in the course of these experiments, as in the work of the investigators already mentioned, that the aldehyde produced is formaldehyde, but it is very important that the possibility of the observed effects being due to some other aldehyde or to a mixture of aldehydes should be borne in mind. This point still requires investigation.