Abamectin is a widely used

insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...

and

anthelmintic Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel parasitic worms (helminths) and other internal parasites from the body by either stunning or killing them and without causing significant damage to the host. They may a ...

. Abamectin, is a member of the

Avermectin The avermectins are a series of drugs and pesticides used to treat parasitic worms and insect pests. They are a group of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring c ...

family and is a natural fermentation product of soil dwelling

actinomycete The Actinomycetales is an order of Actinomycetota. A member of the order is often called an actinomycete. Actinomycetales are generally gram-positive and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycete ...

Streptomyces avermitilis ''Streptomyces avermitilis'' is a species of bacteria in the genus ''Streptomyces''. This bacterium was discovered by Satoshi Ōmura in Shizuoka Prefecture, Japan. The first complete genome sequence of ''S. avermitilis'' was completed in 2003. ...

''. Abamectin (also called

B1), differs from

Ivermectin Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat inf ...

, the popular member of the

family, by double bond on C-22-25. Fermentation of ''

'' yields 8 closely related

homologues out of which B1 (a and b) forms the bulk of the fermentation. The non proprietary name, abamectin, is a combination of Bl_a (~ 80%) and B1_b (~ 20%). Out of all the

s, abamectin is the only one that is used both in agriculture and pharmaceuticals.

Mode of Action

s bind to the glutamate-gated chloride channels that are found in invertebrate nerve and muscle cells. They cause hyperpolarization of these cells resulting in paralysis and death. Mammals only possess glutamate-gated chloride channels in the brain and spinal cord and as the

s have a low affinity for other mammalian ligand-gated channels and do not usually cross the blood–brain barrier, they are very safe for mammals.

History

s were discovered in 1967 in fermentation broths of an actinomycete culture received from the Kitasato Institute in Japan, following an intensive search designed to find natural products with anthelmintic activity. It was not until 1985

ivermectin Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat inf ...

was first used to treat ''Onchocerca volvulus'' (Onchocerciasis or River blindness) in humans by the United Nations. Discoverers of

, William C. Campbell and

Satoshi Ōmura is a Japanese biochemist. He is known for the discovery and development of hundreds of pharmaceuticals originally occurring in microorganisms. In 2015, he was awarded the Nobel Prize in Physiology or Medicine jointly with William C. Campbell fo ...

, shared the 2015 Nobel prize for physiology or medicine.

Activity

Abamectin is an insecticide as well as an

acaricide Acaricides are pesticides that kill members of the arachnid subclass ''Acari'', which includes ticks and mites. Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields. Termino ...

(miticide) and a

nematicide A nematicide is a type of chemical pesticide used to kill plant-parasitic nematodes. Nematicides have tended to be broad-spectrum toxicants possessing high volatility or other properties promoting migration through the soil. Aldicarb (Temik), a car ...

. It is also used to control fire ants. Abamectin is provided orally to horses for deworming them.

Use

Abamectin is also used as a veterinary

antihelmintic Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel parasitic worms (helminths) and other internal parasites from the body by either stunning or killing them and without causing significant damage to the host. They may a ...

. Resistance to abamectin-based antihelmintics, although a growing problem, is not as common as to other classes of veterinary antihelmintics. The benzoate salt

emamectin benzoate Emamectin is the 4”-deoxy-4”-methylamino derivative of abamectin, a 16-membered macrocyclic lactone produced by the fermentation of the soil actinomycete ''Streptomyces avermitilis''. It is generally prepared as the salt with benzoic acid, ema ...

is also used as an insecticide.

s have been used to treat various ailments caused by parasites in both humans and animals.

s including abamectin were studied for use as anti alcohol therapies. Recently, ivermectin is being studied for use as an anti inflammatory agent.

Environmental Fate

Abamectin degrades rapidly when exposed to light (photodegradation) on plant surfaces, in soil, dung and water. Half life of Avermectins (including abamectin) varies between 0.5 to 23 days depending on the rate and substrate (water, soil, faeces or plant). Avermectin B1_a applied at 0.02-0.03 lb ai/acre (50% higher than recommended rates) resulted in very low residue.

Non targets

Abamectin is highly toxic to bees either if they consume or come in direct contact. However, plant parts exposed to abamectin spraying did not cause toxicity to bees 24 hours after treatment. The reason for lower toxicity in foliage is due to a half life <24 hours in plant surfaces.

Trade names

Trade names include Abba, Abathor, Affirm, Agri-Mek, Avid, Dynamec, Epi-Mek, Genesis Horse Wormer, Reaper, Termictine 5%, Vertimec, CAM-MEK 1.8% EC (cam for agrochemicals), Zephyr and Cure 1.8 EC.