What’s that movie about ring in jungle?

I saw an old movie in 90ties I can’t remember now.
Things I remember:
It was an USA, english or australian movie – actors spoke english.
It was a long and boring tv movie, not in cinema.
Quality was like 70s / 80s beginning, a color movie.
The plot was that one evil cripple asked, ordered a group of people for money or blackmail to get a ring which gives immortality.
To get this ring people and main heroes went through different difficulties to get it in Amazon jungle or Africa.
The rich cripple had no legs, maybe had a beard and 70s haircut like Beatles. Upper part of his body was muscular.
The actor seemed legit a disabled person.
He ate and spoke on phone, he yelled.
The ring had something with snake. Maybe green.
In the end heroes get the ring, but are killed and evil cripple gets the ring.
He speaks something puts the ring on his finger, but it has within needle he understands it and get’s poison.
He dies on wheelchair. Film ends.