Two Functionally & Chemically Distinct Immunomodulatory Compounds In The Gel Of Aloe
t’ Hart LA; van Enckevort PH; van Dijk H; Zaat R; de Silva KT; Labadie RP
Department Of Chemical Pharmacy, Faculty Of Pharmacy, State University Of Utrecht
J Ethnopharmacol May-Jun 1988, 23 (1) p61-71

An aqueous extract of Aloe vera gel was analyzed guided by modulatory activity with regard to the in vitro activation of human complement and of human polymorphnuclear leucocytes (PMN). Upon ultrafiltration a high (h-Mr) and a low (l-Mr) molecular mass fraction were obtained. Pre-incubation of human pooled serum with the h-Mr fraction resulted in a depletion of classical and alternative pathway complement activity. In contrast, only the l-Mr fraction could inhibit the production of free oxygen rad-icals by activated PMNs. The latter activity cannot be attributed to non-specific effects like toxicity, interference with stimulant binding or scavenger activity.

Studies On Optimal Dose & Administration Schedule Of A Hematopoietic Stimulatory Beta-(1,4)-Linked Mannan
Egger SF; Brown GS; Kelsey LS; Yates KM; Rosenberg LJ; Talmadge JE
Department Of Pathology & Microbiology, University Of Nebraska Medical Center
Int J Immunopharmacol 18(2):113-26 1996 Feb

Several complex carbohydrates have been found to significantly stimulate hematopoiesis. CARN 750, a polydispersed beta-(1,4)-linked acetylated mannan isolated from the Aloe vera plant, has been shown to have activity in wound repair, to function as a antineoplastic, and to activate macrophages. We report, herein, the hematoaugmenting properties of CARN 750 and its optimal dose and timing of administration in an animal model of irradiation-induced myelosuppression. We observed that subcutaneous injections of 1 mg/animal of CARN 750 had equal or greater stimulatory activity for white blood cell (WBC) counts and spleen cellularity as well as on the absolute numbers of neutrophils, lymphocytes, monocytes and platelets than did higher or lower doses of CARN 750 or an optimal dose of granulocyte-colony stimulating factor (G-CSF). Hematopoietic progenitors, measured as interleukin-3-supported colony forming units-culture (CFU-C) and high proliferative potential colony-forming cells (HPP-CFC) assays, were similarly increased by CARN 750 in the spleen but not in the bone marrow. The frequency of splenic HPP-CFCs and absolute number of splenic HPP-CFCs and CFU-Cs were optimally increased by 1 mg/animal of CARN 750. In contrast, bone marrow cellularity, frequency and absolute number of HPP-CFCs and CFU-Cs had as a dosage optimum 2 mg/animal of CARN 750. These parameters were similarly increased by G-CSF. In studies to determine the optimal protocol for the administration of CARN 750 we found that the hematopoietic activity of CARN 750 increased with the frequency of administration. The greatest activity in myelosuppressed mice was observed for all hematopoietic parameters except the platelet number in mice receiving daily administration of 1 mg/animal of CARN 750 with activity equal to or greater than G-CSF.

Purification & Characterization Of Two Lectins From Aloe Arborescens Mill.
Suzuki I; Saito H; Inoue S; Migita S; Takahashi T
J Biochem (Tokyo) 85(1):163-71 1979 Jan

Two lectins have been isolated from leaves of Aloe arborescens Mill by salt precipitation, pH-dependent fractionation and gel filtration. One lectin (P-2) has a molecular weight of approximately 18,000, consists of two subunits (alphabeta) and contains more than 18% by weight of neutral carbohydrate. The smaller subunit (alpha) has a molecular weight of approximately 7,500 and the larger subunit (beta) a molecular weight of approximately 10,500. The other lectin (S-1) has a molecular weight of approximately 24,000, consists of two subunits (gamma2) with a molecular weight of approximately 12,000 and contains more than 50% by weight of neutral carbohydrate. An interesting feature of the amino acid compositions of these lectins is the high proportion of acidic amino acids, such as aspartic acid and glutamic acid, and the low proportion of methionine and histidine. S-1 has a strong hemagglutinating activity. On the other hand, P-2 has not only hemagglutinating activity but also mitogenic activity on lymphocytes, precipitate-forming reactivity with serum proteins, one of which is alpha2-macroglobulin, and complement C3 activating activity via the alternate pathway.

A 35 kDa Mannose-Binding Lectin With Hemagglutinating & Mitogenic Activities From “Kidachi Aloe” (Aloe Arborescens Miller Var. Natalensis Berger)
Koike T; Beppu H; Kuzuya H; Maruta K; Shimpo K; Suzuki M; Titani K; Fujita K
Institute Of Pharmacognosy, Fujita Health University
J Biochem (Tokyo) 118(6):1205-10 1995 Dec

A novel lectin was isolated from the leaf skin of “Kidachi Aloe” (Aloe arborescens Miller var. natalensis Berger) by sequential chromatographies on Sephadex G-25 gel filtration, DEAE ion exchange, and Superdex 75 gel filtration columns. The native lectin exhibited a molecular mass of about 35 kDa on both gel filtration on a Superdex 75 column and native-PAGE under nonreducing conditions. SDS-PAGE in the presence or absence of beta-mercaptoethanol revealed two distinct peptides with molecular masses of about 5.5 and 2.3 kDa, respectively, in addition to a major 9.2 kDa subunit, indicating the presence of a partially processed subunit. The N-terminal amino acid sequence of the intact subunit showed homology with that of snowdrop lectin. The native lectin showed hemagglutinating activity toward rabbit but not human and sheep erythrocytes, and specifically bound to mannose like snowdrop lectin did, indicating that the Aloe and snowdrop lectins are structurally and functionally similar proteins. In addition, the native lectin showed strong mitogenic activity toward mouse lymphocytes.