Using extract from alkanet as a source of both a red lipid stain and a blue counterstain for histology.

Alkanet () is a plant native to and cultivated in parts of Europe, Asia and the Middle East. It has been used for thousands of years as a medicinal agent and as a colorant for textiles, food and cosmetics. An extract from the root of this plant has been used with a mordant to stain nuclei.

Modeling the extent of conjugation in histochemical dyes and fluorescent probes: clarification in calculating conjugated bond number (CBN) and introduction of a new parameter, resonance energy.

Determining the extent of conjugation in dyes and fluorochromes is a helpful tool for understanding or predicting the behavior of these compounds when used as stains for microscopy. One measure that has been used repeatedly is conjugated bond number (CBN), which is the number of bonds in a conjugated system. CBN can be obtained by inspection of the structure of a compound, but the rules for how to determine what constitutes a conjugated system are not fully established.

Betacyanins are plant-based dyes with potential as histological stains.

Interest is increasing in certain parts of the world in replacing synthetic dyes with dyes from natural sources, particularly from plants. Although textile dyers have used various groups of natural dyes, microscopists generally have restricted their use to anthocyanins. Recently, however, another class of plant-based dyes has found some favor, the betacyanins.

Anthocyanins from a single botanical source can be used as a replacement for hemalum and eosin.

For various reasons, histologists in several parts of the world have tried to replace hematoxylin and eosin with locally available plant dyes of the anthocyanin family. Blue or violet nuclear stains have been created by combining an anthocyanin with iron or aluminum ions at low pH. Obtaining a pink or red cytoplasmic counterstain, however, has not been achieved previously, even with a red solution of anthocyanin, because the chemistry of the colorant does not allow bonding to cytoplasmic materials and collagen.

Molecular stabilization and complexation: the secrets of making a nuclear-selective histological stain from naturally occurring anthocyanins without oxidation.

The natural colorant, roselle, found in , has been used as a histological dye since at least 1976. As a simple extract roselle acts as a general red counterstain, but when treated with an oxidant and metallic mordant it functions as a useful blue nuclear-selective stain. In the past 40 years it has been assumed that oxidation is necessary when preparing a stain from roselle, as of course it is for the related flavonoid dyes hematoxylin and brazilin.

Use of roselle extracted from for histological staining: a critical review and rational stain formulation.

Roselle is the common name for a mixture of anthocyanin dyes derived from the plant, . During the past two decades, a sizable, but conflicting, body of literature has supported the use of roselle as a biological stain, and more specifically as a substitute for hematoxylin for staining nuclei selectively. We review the literature and suggest a rational explanation for divergent findings.

Amyloid from a histochemical perspective. A review of the structure, properties and types of amyloid, and a proposed staining mechanism for Congo red staining.

Amyloid is a diverse group of unrelated peptides or proteins that have positive functionality or are associated with various pathologies. Despite vast differences, all amyloids share several features that together uniquely define the group. 1) All amyloids possess a characteristic cross-ß pattern with X-ray diffraction typical of ß-sheet secondary protein structures.

Alternative methods for estimating common descriptors for QSAR studies of dyes and fluorescent probes using molecular modeling software. 2. Correlations between log P and the hydrophilic/lipophilic index, and new methods for estimating degrees of amphiphilicity.

The log P descriptor, despite its usefulness, can be difficult to use, especially for researchers lacking skills in physical chemistry. Moreover this classic measure has been determined in numerous ways, which can result in inconsistant estimates of log P values, especially for relatively complex molecules such as fluorescent probes. Novel measures of hydrophilicity/lipophilicity (the Hydrophilic/Lipophilic Index, HLI) and amphiphilicity (hydrophilic/lipophilic indices for the head group and tail, HLIT and HLIHG, respectively) therefore have been devised.

Alternative methods for estimating common descriptors for QSAR studies of dyes and fluorescent probes using molecular modeling software: 1. Concepts and procedures.

Quantitative structure activity relations (QSAR) models were developed to predict uptake and intracellular localization of probes or dyes in living cells. Many of the QSAR parameters used in such models are determined manually. Unfortunately, this requires a depth of chemical knowledge that biologists who wish to use these predictive tools do not necessarily possess.