Gas Chromatographic Determination of Nordihydroguaiaretic Acid in Larrea Divaricata

Anti-anaphylactic action of nordihydroguaiaretic acid in antigen sensitized guinea pigs

Therapeutic natural products and medicinal herbs has gained popularity. The anti-antigenic action of the plant alkaloid nordihydroguaiaretic acid (NDGA) was studied in ovalbumin (OA)-sensitized guinea pigs. In one series of experiments conscious, non-sedated guinea pigs were challenged with OA aerosol. Specific airway resistance (SR_AW) was monitored using a two-chambered whole-body plethysmograph. OA aerosol increased SR_AW above that produced by vehicle administration. Prior NDGA administration by a 1min 0.9% aerosol (w/vol) attenuated the increase in SR_AW resulting from OA challenge. In the anesthetized guinea pig pretreated with indomethacin, pyrilamine and propranolol, intravenous OA injection increased intra-tracheal pressure above vehicle injection. Intravenous NDGA administration (5mg/kg) reduced the intra-tracheal pressure increases. In a third series of experiments plasma leukotriene C₄ was measured by radio-immunoassay in 3 groups challenged with OA aerosol: vehicle-treated OA-sensitized, OA-sensitized receiving NDGA and vehicle treated guinea pigs. NDGA pretreatment reduced plasma LTC₄ in response to OA challenge in OA sensitized guinea pigs. This study demonstrates that NDGA is an effective antigenic agent when given by aerosol or intravenous injection in either conscious or anesthetized guinea pigs, respectively. The mechanism of action of NDGA is presumed primarily be due to the blockage of 5-lipoxygenase and therefore the synthesis of leukotrienes.

Different intracellular signals coupled to the antiproliferative action of aqueous crude extract from Larrea divaricata Cav. and nor-dihydroguaiaretic acid on a lymphoma cell line

In this paper, we report the effect of standard NDGA, as compared to that of an aqueous extract of Larrea divaricata Cav., on BW 5147 lymphoma cell-line proliferation. To determine the mechanism of action, the effects of both on the level of intracellular cAMP, protein kinase C activity and calcium influx were studied. Moreover, the NDGA present in the aqueous extract of the plant was quantified. The aqueous extract and the standard NDGA showed antiproliferative action against these cells. While the antiproliferative activity of the aqueous extract was mediated by an increase in cAMP levels, and inhibition of PKC and calcium influx, the antiproliferative activity of NDGA was related only to the inhibition of PKC. Considering the amount of NDGA detected in the aqueous extract of the plant, at the concentrations analyzed in this case, antiproliferative activity of Larrea divaricata cannot be attributed to this compound, but could have an additive effect on the activity of other compounds.

Endotoxin provocation of experimental renal cystic disease

Germ free rats provide a unique model in which to assess biological response to environment. In 48 germ-free male, Sprague-Dawley rats we examined the consequences of oral exposure to nordihydroguaiaretic acid (NDGA), a nephrotoxin; to Staphylococcus epidermidis and bacillus species, non-endotoxin-containing bacteria; to Escherichia coli and Proteus mirabilis, endotoxin-containing bacteria; and injected E. coli endotoxin on peripheral leukocyte counts and renal morphology. Morphological changes were evaluated by light microscopy and scored blindly on a 0 to 4+ scale for 15 parameters of renal structure. Means of these renal "pathology scores" correlated with counts of polymorphonuclear leukocytes and lymphocytes in the peripheral blood. The highest counts and scores were found in rats given NDGA and exposed to endotoxin, either by injection or by oral feeding of endotoxin-containing bacteria. Counts and scores were lower in the absence of endotoxin and with non-endotoxin-containing bacteria, given alone or in combination with either NDGA or endotoxin. Results exclude bacterial colonization and intrarenal accumulation of NDGA as causes of nephropathy. They indicate that endotoxin and NDGA act synergistically to provoke renal damage in the germ free NDGA-fed rat and suggest that leukocytes are involved in the process.

Accelerated renal cyst development in deconditioned germ-free rats

The influence of environment on renal cyst growth was assessed in experiments utilizing 56 germ-free and 32 conventional male Sprague-Dawley rats fed 2% nordihydroguaiaretic acid (NDGA). Among three groups of six germ-free rats allowed ad lib intake of NDGA for six weeks and deconditioned (placed into the ambient laboratory environment) at the start, at the midpoint, or not at all, cyst formation and interstitial changes (both severe) were noted only among animals deconditioned at the midpoint. Among 14 germ-free rats that were offered 0.4 g NDGA daily, deconditioned after two weeks, and sacrificed 0 to 15 days thereafter, nephron dilation and thymidine uptake by renal tubular epithelium appeared within one to three days and correlated in magnitude with each other and with the duration of the contamination interval. Deconditioning, a prior period of four or more days of exposure to NDGA in the germ-free state, the duration of the contamination period, and the presence of cecal flora were identified as prerequisites to accelerated cyst formation in this model, while the dose of ingested NDGA, the presence of bacteria within the kidney, an action of bacteria on NDGA within the colon, and the type(s) of organisms colonizing the host were not. These findings provide experimental evidence that environmental circumstance can modulate the expression of renal cystic disease.