From the Linden Flower to Linden Honey – Volatile Constituents of Linden Nectar, the Extract of Bee‐Stomach and Ripe Honey

Abstract

Honey is produced by honeybees (Apis mellifera), which collect nectar from flowers, digest it in their bodies, and deposit it in honeycombs, where it develops into ripe honey. We studied the evolution of the volatile constituents from the nectar of linden blossoms (Tilia cordata) to honey via the 'intermediate' honeybee. The sampling of the contents of the honey stomach or honey sack of the bee is unique. Extracts were prepared from nectar, from the liquid of the honey stomach, and from ripe honey. The chemistry is extremely complex, and compounds spanning from monoterpenes (hydrocarbons, ethers, aldehydes, acids, and bifunctional derivatives), isoprenoids, aromatic compounds (phenylpropanoids, phenols), and products degraded from fatty acids to alkaloids, were identified. Some compounds definitely stem from the plants, whereas other interesting constituents can be attributed to animal origin. Two derivatives of decanoic acid, 9-oxodec-2-enoic acid (12) and 9-hydroxydec-2-enoic acid, identified in the honey are known to be constituents of the so-called 'Queen's pheromone'. Two metabolites of these acids were identified in the extract of the honey stomach: 8-oxononanal (10), a new natural product, and 8-oxononanol (11). There structures were confirmed by synthesis. Nectar and honey stomach contain many aldehydes, which, due to the highly oxidative atmosphere in the honeycomb, are found as corresponding acids in the honey. Two acids were newly identified as 4-isopropenylcyclohexa-1,3-diene-1-carboxylic acid (14) and 4-(1-hydroxy-1-methylethyl)-cyclohexa-1,3-diene-1-carboxylic acid (15).

The Effects of Nectar–Nicotine on Colony Fitness of Caged Honeybees

“…Baker and Baker (1975) suggested that the level of tolerance to SC in nectar by pollinators is related to their pollination efficiency. In our experiments, we used the European race of bees (A. mellifera ligustica), which may encounter nicotine naturally in nectar of Nicotiana tabacum (Detzel and Wink, 1993) and T. cordata (Naef et al, 2004). Although these plants are native to tropical America and Europe, respectively, they have been introduced and are cultivated in many areas, including Israel.…”

“…Although birds and Lepidoptera are the typical pollinators of most Nicotiana species, honeybees also consume nectar of N. tabacum (Bhuiyan et al, 2002;Oddo et al, 2004) and possibly of N. sylvesteris (Jakobsen et al, 1995) and N. suaveolens (Loughrin et al, 1991(Loughrin et al, , 1993. Honeybees also actively collect nectar containing nicotine from Tilia cordata (Naef et al, 2004; the precise concentration is not known). Detzel and Wink (1993) assessed the toxicity of nicotine in sucrose solutions for caged bees after an exposure of 48 hr.…”

Nectar chemistry

“…Aloe vryheidensis, which contains phenolics-honeybees and sunbirds were Wildner, 1956;Baker & Baker, 1975;Carter & Thornburg, 2004a;Naef et al, 2004;Horner et al, 2007); it is, however, not known how widespread ascorbate accumulation is in nectar. Most of the ascorbate is lost when honeybees convert nectar into honey.…”

Do linden trees kill bees? Reviewing the causes of bee deaths on silver linden (Tilia tomentosa)

“…Intriguingly, Naef et al [41] reported caffeine (figure 1) in T. cordata nectar, and Mathon et al [72] detected caffeine in Tilia sp. flower tea.…”